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__index_level_0__
int64
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13.4k
vKUBJgogUkTqMHWSIq45x
maths
permutations-and-combinations
divisibility-of-numbers
The number of numbers between 2,000 and 5,000 that can be formed with the digits 0, 1, 2, 3, 4 (repetition of digits is not allowed) and are multiple of 3 is :
[{"identifier": "A", "content": "24"}, {"identifier": "B", "content": "30"}, {"identifier": "C", "content": "36"}, {"identifier": "D", "content": "48"}]
["B"]
null
Here number should be divisible by 3, that means sum of numbers should be divisible by 3. <br><br>Possible 4 digits among 0, 1, 2, 3, 4 which are divisible by 3 are <br><br>(1)$$\,\,\,\,$$ (0, 2, 3, 4) Sum of digits = 0 + 2 + 3 +4 = 9 (divisible by 3) <br><br>(2) $$\,\,\,\,$$ (0, 1, 2, 3) Sum of digits = 0 + 1 + 2 + 3...
mcq
jee-main-2018-online-16th-april-morning-slot
7,454
OjrcXgele0CMwAVPCy1kluvyg3b
maths
permutations-and-combinations
divisibility-of-numbers
A natural number has prime factorization given by n = 2<sup>x</sup>3<sup>y</sup>5<sup>z</sup>, where y and z are such <br/>that y + z = 5 and y<sup>$$-$$1</sup> + z<sup>$$-$$1</sup> = $${5 \over 6}$$, y &gt; z. Then the number of odd divisions of n, including 1, is :
[{"identifier": "A", "content": "11"}, {"identifier": "B", "content": "6"}, {"identifier": "C", "content": "12"}, {"identifier": "D", "content": "6x"}]
["C"]
null
y + z = 5 ....... (1)<br><br>$${1 \over y} + {1 \over z} = {5 \over 6}$$<br><br>$$ \Rightarrow {{y + z} \over {yz}} = {5 \over 6}$$<br><br>$$ \Rightarrow {5 \over {yz}} = {5 \over 6}$$<br><br>$$ \Rightarrow $$ yz = 6<br><br>Also, (y $$-$$ z)<sup>2</sup> = (y + z)<sup>2</sup> $$-$$ 4yz<br><br>$$ \Rightarrow $$ (y $$-$$ ...
mcq
jee-main-2021-online-26th-february-evening-slot
7,455
1krygm1ew
maths
permutations-and-combinations
divisibility-of-numbers
Let n be a non-negative integer. Then the number of divisors of the form "4n + 1" of the number (10)<sup>10</sup> . (11)<sup>11</sup> . (13)<sup>13</sup> is equal to __________.
[]
null
924
N = 2<sup>10</sup> $$\times$$ 5<sup>10</sup> $$\times$$ 11<sup>11</sup> $$\times$$ 13<sup>13</sup><br><br>Now, power of 2 must be zero,<br><br>power of 5 can be anything,<br><br>power of 13 can be anything<br><br>But, power of 11 should be even.<br><br>So, required number of divisors is <br><br>1 $$\times$$ 11 $$\times...
integer
jee-main-2021-online-27th-july-evening-shift
7,456
1ldsg0itd
maths
permutations-and-combinations
divisibility-of-numbers
<p>The total number of 4-digit numbers whose greatest common divisor with 54 is 2, is __________.</p>
[]
null
3000
<p>$$\gcd (a,54) = 2$$ when a is a 4 digit no.</p> <p>And $$54 = 3 \times 3 \times 3 \times 2$$</p> <p>So, $$a=$$ all even no. of 4 digits $$-$$ Even multiple of 3 (4 digits)</p> <p>$$ = 4500 - 1500$$</p> <p>$$ = 3000$$</p>
integer
jee-main-2023-online-29th-january-evening-shift
7,458
uKpYZD2xI25YxVqSvGYd0
maths
permutations-and-combinations
factorial
The sum $$\sum\limits_{r = 1}^{10} {\left( {{r^2} + 1} \right) \times \left( {r!} \right)} $$ is equal to :
[{"identifier": "A", "content": "(11)!"}, {"identifier": "B", "content": "10 $$ \\times $$ (11!)"}, {"identifier": "C", "content": "101 $$ \\times $$ (10!)"}, {"identifier": "D", "content": "11 $$ \\times $$ (11!)\n"}]
["B"]
null
$$\sum\limits_{r = 1}^{10} {\left( {{r^2} + 1} \right)} \times r!$$ <br><br>$$ = \sum\limits_{r = 1}^{10} {\left[ {{{\left( {r + 1} \right)}^2} - 2r} \right]\,.\,r!} $$ <br><br>$$ = \sum\limits_{r = 1}^{10} {\left[ {{{\left( {r + 1} \right)}^2}\,.\,r!\,\, - \,\,2r\,.\,r!} \right]} $$ <br><br>$$ = \sum\limits_{r = 1}^{...
mcq
jee-main-2016-online-10th-april-morning-slot
7,459
jaoe38c1lscnqca5
maths
permutations-and-combinations
factorial
<p>Let $$\alpha=\frac{(4 !) !}{(4 !)^{3 !}}$$ and $$\beta=\frac{(5 !) !}{(5 !)^{4 !}}$$. Then :</p>
[{"identifier": "A", "content": "$$\\alpha \\in \\mathbf{N}$$ and $$\\beta \\in \\mathbf{N}$$\n"}, {"identifier": "B", "content": "$$\\alpha \\in \\mathbf{N}$$ and $$\\beta \\notin \\mathbf{N}$$\n"}, {"identifier": "C", "content": "$$\\alpha \\notin \\mathbf{N}$$ and $$\\beta \\in \\mathbf{N}$$\n"}, {"identifier": "D",...
["A"]
null
<p>$$\begin{aligned} & \alpha=\frac{(4 !) !}{(4 !)^{3 !}}, \beta=\frac{(5 !) !}{(5 !)^{4 !}} \\ & \alpha=\frac{(24) !}{(4 !)^6}, \beta=\frac{(120) !}{(5 !)^{24}} \end{aligned}$$</p> <p>Let 24 distinct objects are divided into 6 groups of 4 objects in each group.</p> <p>No. of ways of formation of group $$=\frac{24 !}{(...
mcq
jee-main-2024-online-27th-january-evening-shift
7,460
jaoe38c1lsd4qjvk
maths
permutations-and-combinations
factorial
<p>If for some $$m, n ;{ }^6 C_m+2\left({ }^6 C_{m+1}\right)+{ }^6 C_{m+2}&gt;{ }^8 C_3$$ and $${ }^{n-1} P_3:{ }^n P_4=1: 8$$, then $${ }^n P_{m+1}+{ }^{\mathrm{n}+1} C_m$$ is equal to</p>
[{"identifier": "A", "content": "380"}, {"identifier": "B", "content": "376"}, {"identifier": "C", "content": "372"}, {"identifier": "D", "content": "384"}]
["C"]
null
<p>$$\begin{aligned} & { }^6 \mathrm{C}_{\mathrm{m}}+2\left({ }^6 \mathrm{C}_{\mathrm{m}+1}\right)+{ }^6 \mathrm{C}_{\mathrm{m}+2}>{ }^8 \mathrm{C}_3 \\ & { }^7 \mathrm{C}_{\mathrm{m}+1}+{ }^7 \mathrm{C}_{\mathrm{m}+2}>{ }^8 \mathrm{C}_3 \\ & { }^8 \mathrm{C}_{\mathrm{m}+2}>{ }^8 \mathrm{C}_3 \\ & \therefore \mathrm{m}...
mcq
jee-main-2024-online-31st-january-evening-shift
7,461
txW7MxHrrC595ct0
maths
permutations-and-combinations
number-of-combinations
If $${}^n{C_r}$$ denotes the number of combination of n things taken r at a time, then the expression $$\,{}^n{C_{r + 1}} + {}^n{C_{r - 1}} + 2\, \times \,{}^n{C_r}$$ equals
[{"identifier": "A", "content": "$$\\,{}^{n + 1}{C_{r + 1}}$$ "}, {"identifier": "B", "content": "$${}^{n + 2}{C_r}$$ "}, {"identifier": "C", "content": "$${}^{n + 2}{C_{r + 1}}$$ "}, {"identifier": "D", "content": "$$\\,{}^{n + 1}{C_r}$$ "}]
["C"]
null
Arrange it this way, <br><br>$$^n{C_{r + 1}} + 2.{}^n{C_r} + {}^n{C_{r - 1}}$$ <br><br>$$ = {}^n{C_{r + 1}} + {}^n{C_r} + {}^n{C_r} + {}^n{C_{r - 1}}$$ <br><br>$$\left[ \, \right.$$ Now use the rule, <br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$$\left. {{}^n{C_r} + {}^n{C_{r - 1}} = {}^{n + 1}{C_r}} \right...
mcq
aieee-2003
7,462
cxhMyG1Oo7EJnOxq
maths
permutations-and-combinations
number-of-combinations
The number of ways of distributing 8 identical balls in 3 distinct boxes so that none of the boxes is empty is
[{"identifier": "A", "content": "$${}^8{C_3}$$ "}, {"identifier": "B", "content": "21"}, {"identifier": "C", "content": "$${3^8}$$ "}, {"identifier": "D", "content": "5 "}]
["B"]
null
To distribute n objects among p people where everyone should get atleast one object, then number of ways to distribute those n objects <br><br>= $${}^{n - 1}{C_{p - 1}}$$ <br><br>For this question, n = 8 and p = 3 <br><br>$$ \therefore $$ Number of ways = $${}^{8 - 1}{C_{3 - 1}}$$ = $${}^7{C_2}$$ = 21
mcq
aieee-2004
7,463
WAd9iWoQGJdqmxc0
maths
permutations-and-combinations
number-of-combinations
At an election, a voter may vote for any number of candidates, not greater than the number to be elected. There are 10 candidates and 4 are of be selected, if a voter votes for at least one candidate, then the number of ways in which he can vote is
[{"identifier": "A", "content": "5040"}, {"identifier": "B", "content": "6210"}, {"identifier": "C", "content": "385"}, {"identifier": "D", "content": "1110"}]
["C"]
null
A voter can give vote to either 1 candidate or 2 candidates or 3 candidates or 4 candidates. <br><br>Case 1 : When he give vote to only 1 candidate then no ways = $${}^{10}{C_1}$$ <br><br>Case 2 : When he give vote to 2 candidates then no ways = $${}^{10}{C_2}$$ <br><br>Case 3 : When he give vote to 3 candidates then n...
mcq
aieee-2006
7,464
wZ6fkRvOqG6GRUaw
maths
permutations-and-combinations
number-of-combinations
The set S = {1, 2, 3, ........., 12} is to be partitioned into three sets A, B, C of equal size. Thus $$A \cup B \cup C = S,\,A \cap B = B \cap C = A \cap C = \phi $$. The number of ways to partition S is
[{"identifier": "A", "content": "$${{12!} \\over {{{(4!)}^3}}}\\,\\,$$ "}, {"identifier": "B", "content": "$${{12!} \\over {{{(4!)}^4}}}\\,\\,$$ "}, {"identifier": "C", "content": "$${{12!} \\over {3!\\,\\,{{(4!)}^3}}}$$ "}, {"identifier": "D", "content": "$${{12!} \\over {3!\\,\\,{{(4!)}^4}}}$$ "}]
["A"]
null
<p>The total number of ways is</p> <p>$${}^{12}{C_4} \times {}^{12 - 4}{C_4} \times {}^{12 - 4 - 4}{C_4} = {}^{12}{C_4} \times {}^8{C_4} \times {}^4{C_4} = {{12!} \over {{{(4!)}^3}}}$$</p>
mcq
aieee-2007
7,465
pW3FNSb5ohyzwnDR
maths
permutations-and-combinations
number-of-combinations
In a shop there are five types of ice-cream available. A child buys six ice-cream. <br/> <b> Statement - 1: </b> The number of different ways the child can buy the six ice-cream is $${}^{10}{C_5}$$. <br/> <b> Statement - 2: </b> The number of different ways the child can buy the six ice-cream is equal to the number of ...
[{"identifier": "A", "content": "Statement - 1 is false, Statement - 2 is true "}, {"identifier": "B", "content": "Statement - 1 is true, Statement - 2 is true, Statement - 2 is a correct explanation for Statement - 1"}, {"identifier": "C", "content": "Statement - 1 is true, Statement - 2 is true, Statement - 2 i...
["A"]
null
<b>Note :</b> n items can be distribute among p persons are $${}^{n + p - 1}{C_{p - 1}}$$ ways. <br><br>Here n = 6 ice-cream <br><br>p = 5 types of ice-cream <br><br>Each ice-cream belongs to one of the 5 ice-cream type. So chosen 6 ice-crean can be divide into 5 types of ice-cream. <br><br>$$ \therefore $$ The number ...
mcq
aieee-2008
7,466
gu4xEM8HE3wz9OiX
maths
permutations-and-combinations
number-of-combinations
There are two urns. Urn A has 3 distinct red balls and urn B has 9 distinct blue balls. From each urn two balls are taken out at random and then transferred to the other. The number of ways in which this can be done is
[{"identifier": "A", "content": "36"}, {"identifier": "B", "content": "66"}, {"identifier": "C", "content": "108"}, {"identifier": "D", "content": "3"}]
["C"]
null
<p>Thus number of ways $$ = ({}^3{C_2}) \times ({}^9{C_2}) = 3 \times {{9 \times 8} \over 2} = 108$$</p>
mcq
aieee-2010
7,467
hZ0WqGlvxb9cOBdE
maths
permutations-and-combinations
number-of-combinations
These are 10 points in a plane, out of these 6 are collinear, if N is the number of triangles formed by joining these points. then:
[{"identifier": "A", "content": "$$N \\le 100$$ "}, {"identifier": "B", "content": "$$100 &lt; N \\le 140$$ "}, {"identifier": "C", "content": "$$140 &lt; N \\le 190\\,$$ "}, {"identifier": "D", "content": "$$N &gt; 190$$ "}]
["A"]
null
<p>We need 3 points to create a triangle. With 10 points number of triangle possible $${}^{10}{C_3}$$</p> <p>Here 6 points are on the same line so we can't make any triangle with those 6 points.</p> <p> So subtract $${}^{6}{C_3}$$.</p> <p>$$\therefore$$ $$N = {}^{10}{C_3} - {}^6{C_3}$$</p> <p>$$ = {{10\,.\,9\,.\,8} \ov...
mcq
aieee-2011
7,468
lWJFreINJxGWYGy2
maths
permutations-and-combinations
number-of-combinations
<br/> <b> Statement - 1: </b> The number of ways of distributing 10 identical balls in 4 distinct boxes such that no box is emply is $${}^9{C_3}$$. <br/> <b> Statement - 2: </b> The number of ways of choosing any 3 places from 9 different places is $${}^9{C_3}$$.
[{"identifier": "A", "content": "Statement - 1 is true, Statement - 2 is true, Statement - 2 is not a correct explanation for Statement - 1."}, {"identifier": "B", "content": "Statement - 1 is true, Statement - 2 is false."}, {"identifier": "C", "content": "Statement - 1 is false, Statement - 2 is true."}, {"identi...
["A"]
null
<p>Let XA<sub></sub>, X<sub>B</sub>, X<sub>C</sub> and X<sub>D</sub> represent number of balls present in box A, B, C and D respectively.</p> <p>As no box can be empty so,</p> <p>X<sub>A</sub> $$\ge$$ 1, X<sub>B</sub> $$\ge$$ 1, X<sub>C</sub> $$\ge$$ 1 and X<sub>D</sub> $$\ge$$ 1</p> <p>$$\Rightarrow$$ X<sub>A</sub> $$...
mcq
aieee-2011
7,469
FrmiixXJ0JcQkToz
maths
permutations-and-combinations
number-of-combinations
Assuming the balls to be identical except for difference in colours, the number of ways in which one or more balls can be selected from 10 white, 9 green and 7 black balls is:
[{"identifier": "A", "content": "880"}, {"identifier": "B", "content": "629"}, {"identifier": "C", "content": "630"}, {"identifier": "D", "content": "879"}]
["D"]
null
<p>For alike n objects, number of ways we can select zero or more objects = n + 1 and number of ways we can select at least one object = n</p> <p>Given 10 identical white balls, 9 identical green balls and 7 identical black balls.</p> <p>To find number of ways for selecting atleast one ball.</p> <p>Number of ways to c...
mcq
aieee-2012
7,470
foj68NgT56Ij10bv
maths
permutations-and-combinations
number-of-combinations
Let $${T_n}$$ be the number of all possible triangles formed by joining vertices of an n-sided regular polygon. If $${T_{n + 1}} - {T_n}$$ = 10, then the value of n is :
[{"identifier": "A", "content": "7 "}, {"identifier": "B", "content": "5 "}, {"identifier": "C", "content": "10 "}, {"identifier": "D", "content": "8"}]
["B"]
null
Number of possible triangle using n vertices = <sup>n</sup>C<sub>3</sub> <br><br>$$ \therefore $$ T<sub>n</sub> = <sup>n</sup>C<sub>3</sub> <br><br>then T<sub>n + 1</sub> = <sup>n + 1</sup>C<sub>3</sub> <br><br>Given, $${T_{n + 1}} - {T_n}$$ = 10 <br><br>$$ \Rightarrow $$ <sup>n + 1</sup>C<sub>3</sub> - <sup>n</sup>C<s...
mcq
jee-main-2013-offline
7,472
IYJ08gkoyHdlZ5bWWXi8X
maths
permutations-and-combinations
number-of-combinations
If    $${{{}^{n + 2}C{}_6} \over {{}^{n - 2}{P_2}}}$$ = 11, then n satisfies the equation :
[{"identifier": "A", "content": "n<sup>2</sup> + 3n \u2212 108 = 0"}, {"identifier": "B", "content": "n<sup>2</sup> + 5n \u2212 84 = 0\n"}, {"identifier": "C", "content": "n<sup>2</sup> + 2n \u2212 80 = 0"}, {"identifier": "D", "content": "n<sup>2</sup> + n \u2212 110 = 0"}]
["A"]
null
$${{{}^{n + 2}{C_6}} \over {{}^{n - 2}{P_2}}} = 11$$ <br><br>$$ \Rightarrow $$&nbsp;&nbsp;&nbsp;$${{\left( {n + 2} \right)!} \over {6!\,\left( {n - 4} \right)!}} = 11\,.\,{{\left( {n - 2} \right)!} \over {\left( {n - 4} \right)!}}$$ <br><br>$$ \Rightarrow $$&nbsp;&nbsp;&nbsp;(n + 2)!&nbsp;&nbsp;=&nbsp;&nbsp;11.6! (n $$...
mcq
jee-main-2016-online-10th-april-morning-slot
7,474
hPoq3OSkej5kavXb
maths
permutations-and-combinations
number-of-combinations
A man X has 7 friends, 4 of them are ladies and 3 are men. His wife Y also has 7 friends, 3 of them are ladies and 4 are men. Assume X and Y have no common friends. Then the total number of ways in which X and Y together can throw a party inviting 3 ladies and 3 men, so that 3 friends of each of X and Y are in this par...
[{"identifier": "A", "content": "468"}, {"identifier": "B", "content": "469"}, {"identifier": "C", "content": "484"}, {"identifier": "D", "content": "485"}]
["D"]
null
<table class="tg"> <tbody><tr> <th class="tg-0lax"></th> <th class="tg-s6z2" colspan="2"><span style="font-weight:bold">X(7 Friends)</span></th> <th class="tg-s6z2" colspan="2"><span style="font-weight:bold">Y(7 Friends)</span></th> </tr> <tr> <td class="tg-0lax"></td> <td class="tg-s6z2">4 La...
mcq
jee-main-2017-offline
7,475
nopfCkMOXIUlIZhNggMvD
maths
permutations-and-combinations
number-of-combinations
If  $$\sum\limits_{r = 0}^{25} {\left\{ {{}^{50}{C_r}.{}^{50 - r}{C_{25 - r}}} \right\} = K\left( {^{50}{C_{25}}} \right)} ,\,\,$$ then K is equal to :
[{"identifier": "A", "content": "2<sup>24</sup> "}, {"identifier": "B", "content": "2<sup>25</sup>$$-$$ 1"}, {"identifier": "C", "content": "2<sup>25</sup>"}, {"identifier": "D", "content": "(25)<sup>2</sup>"}]
["C"]
null
$$\sum\limits_{r = 0}^{25} {^{50}} {C_r}.{}^{50 - r}{C_{25 - r}}$$ <br><br>$$ = \sum\limits_{r = 0}^{25} {{{50!} \over {r!\left( {50 - r} \right)!}}} \times {{\left( {50 - r} \right)!} \over {\left( {25} \right)!\left( {25 - r} \right)!}}$$ <br><br>$$ = \sum\limits_{r = 0}^{25} {{{50!} \over {25!25!}} \times {{25!} \o...
mcq
jee-main-2019-online-10th-january-evening-slot
7,476
d9rYjwxlxiAXsKNTjN8AV
maths
permutations-and-combinations
number-of-combinations
Consider three boxes, each containing, 10 balls labelled 1, 2, … , 10. Suppose one ball is randomly drawn from each of the boxes. Denote by n<sub>i</sub>, the label of the ball drawn from the i<sup>th</sup> box, (i = 1, 2, 3). Then, the number of ways in which the balls can be chosen such that n<sub>1</sub> &lt; n<sub>...
[{"identifier": "A", "content": "164"}, {"identifier": "B", "content": "240"}, {"identifier": "C", "content": "82"}, {"identifier": "D", "content": "120"}]
["D"]
null
Number of ways = <sup>10</sup>C<sub>3</sub> = 120
mcq
jee-main-2019-online-12th-january-morning-slot
7,477
wyrLSbxVQxkAIJHo7FrTT
maths
permutations-and-combinations
number-of-combinations
There are m men and two women participating in a chess tournament. Each participant plays two games with every other participant. If the number of games played by the men between themselves exceeds the number of games played between the men and the women by 84, then the value of m is :
[{"identifier": "A", "content": "12"}, {"identifier": "B", "content": "9"}, {"identifier": "C", "content": "7"}, {"identifier": "D", "content": "11"}]
["A"]
null
Let m-men, 2-women <br><br><sup>m</sup>C<sub>2</sub> $$ \times $$ 2 = <sup>m</sup><sup></sup>C<sub>1</sub> <sup>2</sup>C<sub>1</sub> . 2 + 84 <br><br>m<sup>2</sup> $$-$$ 5m $$-$$ 84 = 0 $$ \Rightarrow $$ (m $$-$$ 12) (m + 7) = 0 <br><br>m = 12
mcq
jee-main-2019-online-12th-january-evening-slot
7,478
IiAhsoFZAqNRGsldWG3rsa0w2w9jx5e78h8
maths
permutations-and-combinations
number-of-combinations
The number of ways of choosing 10 objects out of 31 objects of which 10 are identical and the remaining 21 are distinct, is :
[{"identifier": "A", "content": "2<sup>20</sup> - 1"}, {"identifier": "B", "content": "2<sup>20</sup>"}, {"identifier": "C", "content": "2<sup>20</sup> + 1"}, {"identifier": "D", "content": "2<sup>21</sup> "}]
["B"]
null
<sup>21</sup>C<sub>0</sub> + <sup>21</sup>C<sub>1</sub> + <sup>21</sup>C<sub>2</sub> + ....... + <sup>21</sup>C<sub>10</sub> = $${{{2^{21}}} \over 2} = {2^{20}}$$
mcq
jee-main-2019-online-12th-april-morning-slot
7,479
Df2NYHYq0uAHcIQV3H7k9k2k5gjegt5
maths
permutations-and-combinations
number-of-combinations
If a, b and c are the greatest value of <sup>19</sup>C<sub>p</sub>, <sup>20</sup>C<sub>q</sub> and <sup>21</sup>C<sub>r</sub> respectively, then :
[{"identifier": "A", "content": "$${a \\over {11}} = {b \\over {22}} = {c \\over {21}}$$"}, {"identifier": "B", "content": "$${a \\over {10}} = {b \\over {22}} = {c \\over {21}}$$"}, {"identifier": "C", "content": "$${a \\over {10}} = {b \\over {11}} = {c \\over {42}}$$"}, {"identifier": "D", "content": "$${a \\over {1...
["D"]
null
( <sup>19</sup>C<sub>p</sub>)<sub>max</sub> = <sup>19</sup>C<sub>9</sub> or <sup>19</sup>C<sub>10</sub> = a <br><br>( <sup>20</sup>C<sub>p</sub>)<sub>max</sub> = <sup>20</sup>C<sub>10</sub> = b <br><br>( <sup>21</sup>C<sub>r</sub>)<sub>max</sub> = <sup>21</sup>C<sub>10</sub> or <sup>21</sup>C<sub>11</sub> = c <br><br>1...
mcq
jee-main-2020-online-8th-january-morning-slot
7,481
TgQzv9xzFjU3klQ0D27k9k2k5h0eczd
maths
permutations-and-combinations
number-of-combinations
An urn contains 5 red marbles, 4 black marbles and 3 white marbles. Then the number of ways in which 4 marbles can be drawn so that at the most three of them are red is ___________.
[]
null
490
Here 5 red marbels and 7 non red marbels presents. <br><br>No of ways 4 marbels can be chosen where atmost 3 red marbels can be present. <br><br><b>Case 1:</b> When 3 red marbels present <br><br>No of ways = <sup>5</sup>C<sub>3</sub> $$ \times $$ <sup>7</sup>C<sub>1</sub> <br><br><b>Case 2:</b> When 2 red marbels pres...
integer
jee-main-2020-online-8th-january-morning-slot
7,482
SLjj7ptO9uQcIkLlhTjgy2xukfakunkv
maths
permutations-and-combinations
number-of-combinations
A test consists of 6 multiple choice questions, each having 4 alternative answers of which only one is correct. The number of ways, in which a candidate answers all six questions such that exactly four of the answers are correct, is __________.
[]
null
135
Select any 4 questions in <sup>6</sup>C<sub>4</sub> ways which are correct. <br><br>Answering right option for each question is possible in 1 way. <br><br>So ways of choosing right option for 4 questions = 1.1.1.1 = (1)<sup>4</sup> <br><br>Number of ways of choosing wrong option for each question = 3 <br><br>So ways o...
integer
jee-main-2020-online-4th-september-evening-slot
7,483
FlAz2HmdDhqlvaBRdA1kmjbf0bo
maths
permutations-and-combinations
number-of-combinations
Team 'A' consists of 7 boys and n girls and Team 'B' has 4 boys and 6 girls. If a total of 52 single matches can be arranged between these two teams when a boy plays against a boy and a girl plays against a girl, then n is equal to :
[{"identifier": "A", "content": "5"}, {"identifier": "B", "content": "2"}, {"identifier": "C", "content": "4"}, {"identifier": "D", "content": "6"}]
["C"]
null
Total matches between boys of both team = $${}^7{C_1} \times {}^4{C_1} = 28$$<br><br>Total matches between girls of both team = $${}^n{C_1}\,{}^6{C_1} = 6n$$<br><br>Now, 28 + 6n = 52<br><br>$$ \Rightarrow $$ n = 4
mcq
jee-main-2021-online-17th-march-morning-shift
7,484
1krzq59sa
maths
permutations-and-combinations
number-of-combinations
If $${}^n{P_r} = {}^n{P_{r + 1}}$$ and $${}^n{C_r} = {}^n{C_{r - 1}}$$, then the value of r is equal to :
[{"identifier": "A", "content": "1"}, {"identifier": "B", "content": "4"}, {"identifier": "C", "content": "2"}, {"identifier": "D", "content": "3"}]
["C"]
null
$${}^n{P_r} = {}^n{P_{r + 1}} \Rightarrow {{n!} \over {(n - r)!}} = {{n!} \over {(n - r - 1)!}}$$<br><br>$$ \Rightarrow (n - r) = 1$$ .....(1)<br><br>$${}^n{C_r} = {}^n{C_{r - 1}}$$<br><br>$$ \Rightarrow {{n!} \over {r!(n - r)!}} = {{n!} \over {(r - 1)!(n - r + 1)!}}$$<br><br>$$ \Rightarrow {1 \over {r(n - r)!}} = {1 \...
mcq
jee-main-2021-online-25th-july-evening-shift
7,485
1l6p3l4h6
maths
permutations-and-combinations
number-of-combinations
<p>The number of matrices of order $$3 \times 3$$, whose entries are either 0 or 1 and the sum of all the entries is a prime number, is __________.</p>
[]
null
282
<p>In a $$3\times3$$ order matrix there are $$9$$ entries.</p> <p>These nine entries are zero or one.</p> <p>The sum of positive prime entries are $$2, 3, 5$$ or $$7$$.</p> <p>Total possible matrices $$ = {{9!} \over {2!\,.\,7!}} + {{9!} \over {3!\,.\,6!}} + {{9!} \over {5!\,.\,4!}} + {{9!} \over {7!\,.\,2!}}$$</p> <...
integer
jee-main-2022-online-29th-july-morning-shift
7,487
ldoaldz7
maths
permutations-and-combinations
number-of-combinations
Let $\mathrm{A}=\left[\mathrm{a}_{i j}\right], \mathrm{a}_{i j} \in \mathbb{Z} \cap[0,4], 1 \leq i, j \leq 2$. <br/><br/>The number of matrices A such that the sum of all entries is a prime number $\mathrm{p} \in(2,13)$ is __________.
[]
null
204
$A=\left[\begin{array}{ll}a_{11} & a_{12} \\ a_{13} & a_{14}\end{array}\right]$ <br/><br/>Such that $\Sigma a_{i i}=3,5,7$ or 11 <br/><br/>Then for sum 3, the possible entries are $(0,0,0,3)$, $(0,0,1,2),(0,1,1,1)$. <br/><br/>Then total number of possible matrices $$ =4+12+4 $$ $=20$ <br/><br/>For sum 5 the poss...
integer
jee-main-2023-online-31st-january-evening-shift
7,488
1ldu5w6ww
maths
permutations-and-combinations
number-of-combinations
<p>$$\sum\limits_{k = 0}^6 {{}^{51 - k}{C_3}} $$ is equal to :</p>
[{"identifier": "A", "content": "$$\\mathrm{{}^{51}{C_4} - {}^{45}{C_4}}$$"}, {"identifier": "B", "content": "$$\\mathrm{{}^{51}{C_3} - {}^{45}{C_3}}$$"}, {"identifier": "C", "content": "$$\\mathrm{{}^{52}{C_3} - {}^{45}{C_3}}$$"}, {"identifier": "D", "content": "$$\\mathrm{{}^{52}{C_4} - {}^{45}{C_4}}$$"}]
["D"]
null
$$ \begin{aligned} & \sum_{\mathrm{k}=0}^6{ }^{51-\mathrm{k}} \mathrm{C}_3 \\\\ & ={ }^{51} \mathrm{C}_3+{ }^{50} \mathrm{C}_3+{ }^{49} \mathrm{C}_3+\ldots+{ }^{45} \mathrm{C}_3 \\\\ & ={ }^{45} \mathrm{C}_3+{ }^{46} \mathrm{C}_3+\ldots \ldots+{ }^{51} \mathrm{C}_3 \\\\ & ={ }^{45} \mathrm{C}_4+{ }^{45} \mathrm{C}_3+{ ...
mcq
jee-main-2023-online-25th-january-evening-shift
7,489
1lgzzp7q6
maths
permutations-and-combinations
number-of-combinations
<p>Let the number of elements in sets $$A$$ and $$B$$ be five and two respectively. Then the number of subsets of $$A \times B$$ each having at least 3 and at most 6 elements is :</p>
[{"identifier": "A", "content": "782"}, {"identifier": "B", "content": "772"}, {"identifier": "C", "content": "752"}, {"identifier": "D", "content": "792"}]
["D"]
null
<p>First, let's determine the number of elements in the Cartesian product $$A \times B$$. If set $$A$$ has 5 elements and set $$B$$ has 2 elements, then the number of elements in $$A \times B$$ is:</p> <p> <p>$$|A \times B| = |A| \times |B| = 5 \times 2 = 10$$</p> </p> <p>We need to find the number of subsets of $$...
mcq
jee-main-2023-online-8th-april-morning-shift
7,492
lsaoelst
maths
permutations-and-combinations
number-of-combinations
If $\mathrm{n}$ is the number of ways five different employees can sit into four indistinguishable offices where any office may have any number of persons including zero, then $\mathrm{n}$ is equal to :
[{"identifier": "A", "content": "47"}, {"identifier": "B", "content": "53"}, {"identifier": "C", "content": "51"}, {"identifier": "D", "content": "43"}]
["C"]
null
<p>To determine the number of ways in which five different employees can be seated in four indistinguishable offices, we will use the concept of partitioning of an integer.</p> <p>The problem is equivalent to partitioning the number 5 (representing the 5 different employees) into at most 4 parts (representing the 4 in...
mcq
jee-main-2024-online-1st-february-morning-shift
7,493
lsapvsz6
maths
permutations-and-combinations
number-of-combinations
The number of elements in the set $\mathrm{S}=\{(x, y, z): x, y, z \in \mathbf{Z}, x+2 y+3 z=42, x, y, z \geqslant 0\}$ equals __________.
[]
null
169
$$ x+2 y+3 z=42 $$ <br/><br/>$$ x, y, z \geq 0 $$ <br/><br/>as <br/><br/>$\begin{array}{ll}z=0 & x+2 y=42 \Rightarrow 22 \text { cases } \\\\ z=1 & x+2 y=39 \Rightarrow 20 \text { cases } \\\\ z=2 & x+2 y=36 \Rightarrow 19 \text { cases } \\\\ z=3 & x+2 y=33 \Rightarrow 17 \text { cases } \\\\ z=4 & x+2 y=30 \Rightarro...
integer
jee-main-2024-online-1st-february-morning-shift
7,494
1lsg4z01p
maths
permutations-and-combinations
number-of-combinations
<p>In an examination of Mathematics paper, there are 20 questions of equal marks and the question paper is divided into three sections : $$A, B$$ and $$C$$. A student is required to attempt total 15 questions taking at least 4 questions from each section. If section $$A$$ has 8 questions, section $$B$$ has 6 questions ...
[]
null
11376
<p>The problem involves choosing 15 questions out of a total of 20 available questions, with the constraint that at least 4 questions must be chosen from each of the three sections A, B, and C. To evaluate the total number of ways a student can select these questions, we need to consider every possible combination of q...
integer
jee-main-2024-online-30th-january-evening-shift
7,496
lv0vxc34
maths
permutations-and-combinations
number-of-combinations
<p>There are 5 points $$P_1, P_2, P_3, P_4, P_5$$ on the side $$A B$$, excluding $$A$$ and $$B$$, of a triangle $$A B C$$. Similarly there are 6 points $$\mathrm{P}_6, \mathrm{P}_7, \ldots, \mathrm{P}_{11}$$ on the side $$\mathrm{BC}$$ and 7 points $$\mathrm{P}_{12}, \mathrm{P}_{13}, \ldots, \mathrm{P}_{18}$$ on the si...
[{"identifier": "A", "content": "751"}, {"identifier": "B", "content": "776"}, {"identifier": "C", "content": "796"}, {"identifier": "D", "content": "771"}]
["A"]
null
<p>Number of points on side $$A B=5$$</p> <p>Number of points on side $$B C=6$$</p> <p>Number of points on side $$A C=7$$</p> <p><img src="https://app-content.cdn.examgoal.net/fly/@width/image/1lwk6ko9r/1d69134a-fee4-473a-84cb-efe47fa9ec3c/ecc716f0-1985-11ef-a7bd-376696e028ce/file-1lwk6ko9s.png?format=png" data-orsrc="...
mcq
jee-main-2024-online-4th-april-morning-shift
7,497
lv2er3yn
maths
permutations-and-combinations
number-of-combinations
<p>There are 4 men and 5 women in Group A, and 5 men and 4 women in Group B. If 4 persons are selected from each group, then the number of ways of selecting 4 men and 4 women is ________.</p>
[]
null
5626
<p><style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial,...
integer
jee-main-2024-online-4th-april-evening-shift
7,498
lv9s208h
maths
permutations-and-combinations
number-of-combinations
<p>Let the set $$S=\{2,4,8,16, \ldots, 512\}$$ be partitioned into 3 sets $$A, B, C$$ with equal number of elements such that $$\mathrm{A} \cup \mathrm{B} \cup \mathrm{C}=\mathrm{S}$$ and $$\mathrm{A} \cap \mathrm{B}=\mathrm{B} \cap \mathrm{C}=\mathrm{A} \cap \mathrm{C}=\phi$$. The maximum number of such possible parti...
[{"identifier": "A", "content": "1640"}, {"identifier": "B", "content": "1520"}, {"identifier": "C", "content": "1710"}, {"identifier": "D", "content": "1680"}]
["D"]
null
<p>Given set $$S=\left\{2^1, 2^2, \ldots 2^9\right\}$$ which consist of 9 elements.</p> <p>Maximum number of possible partitions (in set $$A, B$$ and $$C$$)</p> <p>$$={ }^9 C_3 \cdot{ }^6 C_3 \cdot{ }^3 C_3=1680$$</p>
mcq
jee-main-2024-online-5th-april-evening-shift
7,500
lvb294ut
maths
permutations-and-combinations
number-of-combinations
<p>Let $$0 \leq r \leq n$$. If $${ }^{n+1} C_{r+1}:{ }^n C_r:{ }^{n-1} C_{r-1}=55: 35: 21$$, then $$2 n+5 r$$ is equal to :</p>
[{"identifier": "A", "content": "62"}, {"identifier": "B", "content": "60"}, {"identifier": "C", "content": "55"}, {"identifier": "D", "content": "50"}]
["D"]
null
<p>Given $0 \leq r \leq n$. If $\binom{n+1}{r+1} : \binom{n}{r} : \binom{n-1}{r-1} = 55 : 35 : 21$, then we are to determine the value of $2n + 5r$.</p> <h3>Step-by-Step Solution:</h3> <ol> <li>Write the given proportions involving binomial coefficients:</li> </ol> <p>$ \frac{n+1}{r+1} \times \binom{n}{r} : \binom...
mcq
jee-main-2024-online-6th-april-evening-shift
7,501
MWbLRehjPiKaEgcg
maths
permutations-and-combinations
number-of-permutations
If the letter of the word SACHIN are arranged in all possible ways and these words are written out as in dictionary, then the word SACHIN appears at serial number
[{"identifier": "A", "content": "601"}, {"identifier": "B", "content": "600"}, {"identifier": "C", "content": "603"}, {"identifier": "D", "content": "602"}]
["A"]
null
<picture><source media="(max-width: 320px)" srcset="https://res.cloudinary.com/dckxllbjy/image/upload/v1734263736/exam_images/ru0tccwaposwg6xx5sll.webp"><source media="(max-width: 500px)" srcset="https://res.cloudinary.com/dckxllbjy/image/upload/v1734264497/exam_images/bawohr8zdetwd8ozm1dc.webp"><source media="(max-wid...
mcq
aieee-2005
7,502
KscQ5CpVa6h3aZAR
maths
permutations-and-combinations
number-of-permutations
From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary are to be selected and arranged in a row on a shelf so that the dictionary is always in the middle. Then the number of such arrangement is :
[{"identifier": "A", "content": "at least 500 but less than 750"}, {"identifier": "B", "content": "at least 750 but less than 1000"}, {"identifier": "C", "content": "at least 1000"}, {"identifier": "D", "content": "less than 500"}]
["C"]
null
From 6 different novels 4 novels can be chosen = $${}^6{C_4}$$ ways <br><br>And from 4 different dictionaries 1 can be chosen = $${}^3{C_1}$$ ways <br><br>$$\therefore$$ From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary can be chosen = $${}^6{C_4} \times {}^3{C_1}$$ ways <br><br>Let 4 nove...
mcq
aieee-2009
7,503
cpWdidtToPeRE0b1
maths
permutations-and-combinations
number-of-permutations
The number of integers greater than 6,000 that can be formed, using the digits 3, 5, 6, 7 and 8, without repetition, is:
[{"identifier": "A", "content": "120"}, {"identifier": "B", "content": "72"}, {"identifier": "C", "content": "216"}, {"identifier": "D", "content": "192"}]
["D"]
null
<p>For a four digit number the first place can be filled in 3 ways with 6 or 7 or 8 and the remaining four places in 4! ways i.e., 3 $$\times$$ 4! = 72.</p> <p>For a five digit number it can be arranged in 5! ways,</p> <p>$$\therefore$$ total number of integers = (72 + 120) = 192.</p>
mcq
jee-main-2015-offline
7,504
IplDhMsmdCoRdapu
maths
permutations-and-combinations
number-of-permutations
If all the words (with or without meaning) having five letters,formed using the letters of the word SMALL and arranged as in a dictionary, then the position of the word SMALL is :
[{"identifier": "A", "content": "$${46^{th}}$$ "}, {"identifier": "B", "content": "$${59^{th}}$$"}, {"identifier": "C", "content": "$${52^{nd}}$$"}, {"identifier": "D", "content": "$${58^{th}}$$"}]
["D"]
null
<p>Clearly, number of words start with $$A = {{4!} \over {2!}} = 12$$</p> <p>Number of words start with $$L = 4! = 24$$</p> <p>Number of words start with $$M = {{4!} \over {2!}} = 12$$</p> <p>Number of words start with $$SA = {{3!} \over {2!}} = 3$$</p> <p>Number of words start with $$SL = 3! = 6$$</p> <p>Note that, ne...
mcq
jee-main-2016-offline
7,505
4sIda7kghDbn5SBTSeZMx
maths
permutations-and-combinations
number-of-permutations
If all the words, with or without meaning, are written using the letters of the word QUEEN and are arranged as in English dictionary, then the position of the word QUEEN is :
[{"identifier": "A", "content": "44<sup>th</sup> "}, {"identifier": "B", "content": "45<sup>th</sup> "}, {"identifier": "C", "content": "46<sup>th</sup> "}, {"identifier": "D", "content": "47<sup>th</sup> "}]
["C"]
null
<p>To find the position of the word QUEEN:</p> <p>$$\bullet$$ The number of words starting with E is 4! = 24.</p> <p>$$\bullet$$ The number of words starting with N is $${{4!} \over 2} = 12$$.</p> <p>$$\bullet$$ The number of words starting with QE is 3! = 6.</p> <p>$$\bullet$$ Number of words starting with QN is $${{3...
mcq
jee-main-2017-online-8th-april-morning-slot
7,506
dE3mDjQalcUd2nH6
maths
permutations-and-combinations
number-of-permutations
From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary are to be selected and arranged in a row on a shelf so that the dictionary is always in the middle. The number of such arrangements is :
[{"identifier": "A", "content": "at least 750 but less than 1000"}, {"identifier": "B", "content": "at least 1000"}, {"identifier": "C", "content": "less than 500"}, {"identifier": "D", "content": "at least 500 but less than 750"}]
["B"]
null
From 6 different novels 4 novels can be chosen = $${}^6{C_4}$$ ways <br><br>And from 3 different dictionaries 1 can be chosen = $${}^3{C_1}$$ ways <br><br>$$\therefore$$ From 6 different novels and 3 different dictionaries, 4 novels and 1 dictionary can be chosen = $${}^6{C_4} \times {}^3{C_1}$$ ways <br><br>Let 4 nove...
mcq
jee-main-2018-offline
7,507
XLd4i0VsYtBkRaHaQmAcd
maths
permutations-and-combinations
number-of-permutations
n$$-$$digit numbers are formed using only three digits 2, 5 and 7. The smallest value of n for which 900 such distinct numbers can be formed, is :
[{"identifier": "A", "content": "6"}, {"identifier": "B", "content": "7"}, {"identifier": "C", "content": "8"}, {"identifier": "D", "content": "9"}]
["B"]
null
In n digit number first place can be filled with any one of 2, 5, 7. So no of ways first digit can be filled = 3<br><br> Similarly,<br> no of ways 2nd digit can be filled = 3 ways<br> .<br> .<br> .<br> .<br> - - - - - - nth - - - - - - - = 3 ways<br> <br> $$ \therefore $$ Total numbers = 3 $$ \times $$ 3 $$ \times $...
mcq
jee-main-2018-online-15th-april-morning-slot
7,508
xe5ZfgVxYCdbpMKEGIuOF
maths
permutations-and-combinations
number-of-permutations
The number of four letter words that can be formed using the letters of the word <b>BARRACK</b> is :
[{"identifier": "A", "content": "120"}, {"identifier": "B", "content": "144"}, {"identifier": "C", "content": "264"}, {"identifier": "D", "content": "270"}]
["D"]
null
<b>Case 1 :</b> <br><br>When all the four letters different then no of words <br>= <sup>5</sup>C<sub>4</sub> $$ \times $$4! <br><br><b>Case 2 :</b> <br><br>When out of four letters two letters are R and other two different letters are chosen from B, A, C, K then the no of words <br>= <sup>4</sup>C<sub>2</sub> $$ \times...
mcq
jee-main-2018-online-15th-april-evening-slot
7,509
lrAD8xOCEl2vEKUBAe7k9k2k5e2s565
maths
permutations-and-combinations
number-of-permutations
Total number of 6-digit numbers in which only and all the five digits 1, 3, 5, 7 and 9 appear, is :
[{"identifier": "A", "content": "$${5 \\over 2}\\left( {6!} \\right)$$"}, {"identifier": "B", "content": "$${6!}$$"}, {"identifier": "C", "content": "5<sup>6</sup>"}, {"identifier": "D", "content": "$${1 \\over 2}\\left( {6!} \\right)$$"}]
["A"]
null
Here none number repeats more than once. <br><br>We can choose the number which repeats more than once among 1, 3, 5, 7, 9 in <sup>5</sup>C<sub>1</sub> ways. <br><br>Let number 3 repeats more than once. So six digits are 1, 3, 3, 5, 7, 9. <br><br>We can arrange those six digits in $${{6!} \over {2!}}$$ ways. <br><br>$$...
mcq
jee-main-2020-online-7th-january-morning-slot
7,510
qbRvgJn6hv5comatCj7k9k2k5hketjb
maths
permutations-and-combinations
number-of-permutations
The number of 4 letter words (with or without meaning) that can be formed from the eleven letters of the word 'EXAMINATION' is _______.
[]
null
2454
2A, 2I, 2N, E, X, M, T, O <br><br>To form four letter words <br><br><b>Case 1 :</b> All same ( not possible) <br><br><b>Case 2 :</b> 1 different, 3 same (not possible) <br><br><b>Case 3 :</b> 2 different, 2 same <br><br>= <sup>3</sup>C<sub>1</sub> $$ \times $$ <sup>7</sup>C<sub>2</sub> $$ \times $$ $${{4!} \over {2!}}$...
integer
jee-main-2020-online-8th-january-evening-slot
7,511
k3m0N9G0xSwL4wln7Cjgy2xukewtoyf9
maths
permutations-and-combinations
number-of-permutations
If the letters of the word 'MOTHER' be permuted and all the words so formed (with or without meaning) be listed as in a dictionary, then the position of the word 'MOTHER' is ______.
[]
null
309
<picture><source media="(max-width: 320px)" srcset="https://res.cloudinary.com/dckxllbjy/image/upload/v1734267803/exam_images/xbqcgksmphluv6sci9ir.webp"><source media="(max-width: 500px)" srcset="https://res.cloudinary.com/dckxllbjy/image/upload/v1734265109/exam_images/kdpljpefm6kve0qcetlt.webp"><source media="(max-wid...
integer
jee-main-2020-online-2nd-september-morning-slot
7,512
KcZ71werwgGvco0DDojgy2xukf0wa8ut
maths
permutations-and-combinations
number-of-permutations
The value of (2.<sup>1</sup>P<sub>0</sub> – 3.<sup>2</sup>P<sub>1</sub> + 4.<sup>3</sup>P<sub>2</sub> .... up to 51<sup>th</sup> term)<br/> + (1! – 2! + 3! – ..... up to 51<sup>th</sup> term) is equal to :
[{"identifier": "A", "content": "1"}, {"identifier": "B", "content": "1 + (51)!"}, {"identifier": "C", "content": "1 \u2013 51(51)!"}, {"identifier": "D", "content": "1 + (52)!"}]
["D"]
null
(2.<sup>1</sup>P<sub>0</sub> – 3.<sup>2</sup>P<sub>1</sub> + 4.<sup>3</sup>P<sub>2</sub> .... up to 51<sup>th</sup> term)<br> + (1! – 2! + 3! – ..... up to 51<sup>th</sup> term) <br><br>= ( 2.1! - 3.2! + 4.3! - ....+ 52.51!) <br>+ ( 1! – 2! + 3! – ..... + (51)! ) <br><br>= (2! - 3! + 4! .....+ 52! ) <br>+ ( 1! - 2! + ...
mcq
jee-main-2020-online-3rd-september-morning-slot
7,513
t2DoGkNqDTClpiz752jgy2xukf49ludb
maths
permutations-and-combinations
number-of-permutations
The total number of 3-digit numbers, whose sum of digits is 10, is __________.
[]
null
54
Let xyz is 3 digits number.<br><br>Given that sum of digits = 10<br><br>$$ \therefore $$ x + y + z = 10 ......(1)<br><br>Also x can't be 0 as if x = 0 then it will become 2 digits number.<br><br>So, x $$ \ge $$ 1, y $$ \ge $$ 0, z $$ \ge $$ 0<br><br>As x $$ \ge $$ 1<br><br>$$ \Rightarrow $$ x $$-$$ 1 $$ \ge $$ 0<br><br...
integer
jee-main-2020-online-3rd-september-evening-slot
7,514
HzI0OnXimst1pZw1d21kmllyfaz
maths
permutations-and-combinations
number-of-permutations
The missing value in the following figure is <br/><br/><img src="data:image/png;base64,UklGRqYYAABXRUJQVlA4IJoYAACQiACdASqcAVsBPm00lkikIqKhITJLIIANiWlu/HRYhs4NYEDwnk/Ff8+/GTwA/tn9O/bD+u9kB4u/T/2s/uHsA/038e9AnPv+1/j3qp8z/wv8O/qv+5/wf7s/fb89/yP8b/nf+0/sfp78RvkD2CPTf+M/hv9Y/0f9O/df2+f7j+AfyLwM7GfoB7BHbv/L/xX+ffr58Qnpf+h/i...
[]
null
4
Inside number $=\left(\right.$ difference)${ }^{(\text {difference}) !}$ <br/><br/>$=($Greater number - Smaller number)<sup>(Greater number - Smaller number)!</sup> <br/><br/>i.e. $1=(2-1)^{(2-1) !}, $ <br/><br/>$4^{24}=(12-8)^{(12-8) !}, $ <br/><br/>$3^6=(7-4)^{(7-4) !}$ <br/><br/>$\therefore \quad ?=(5-3)^{(5-3) !}$ ...
integer
jee-main-2021-online-18th-march-morning-shift
7,515
1ktbicc13
maths
permutations-and-combinations
number-of-permutations
If $${}^1{P_1} + 2.{}^2{P_2} + 3.{}^3{P_3} + .... + 15.{}^{15}{P_{15}} = {}^q{P_r} - s,0 \le s \le 1$$, then $${}^{q + s}{C_{r - s}}$$ is equal to ______________.
[]
null
136
$${}^1{P_1} + 2.{}^2{P_2} + 3.{}^3{P_3} + .... + 15.{}^{15}{P_{15}}$$<br><br>= 1! + 2 . 2! + 3 . 3! + ..... 15 $$\times$$ 15!<br><br>$$ = \sum\limits_{r = 1}^{15} {(r + 1)! - (r)!} $$<br><br>= 16! $$-$$ 1<br><br>= $${}^{16}{P_{16}}$$ $$-$$ 1<br><br>$$\Rightarrow$$ q = r = 16, s = 1<br><br>$${}^{q + s}{C_{r - s}} = {}^{...
integer
jee-main-2021-online-26th-august-morning-shift
7,517
1l6dx41xx
maths
permutations-and-combinations
number-of-permutations
<p>The letters of the word 'MANKIND' are written in all possible orders and arranged in serial order as in an English dictionary. Then the serial number of the word 'MANKIND' is _____________.</p>
[]
null
1492
<p>Step 1 :</p> <p>Write all the alphabets in alphabetical order.</p> <p><img src="https://app-content.cdn.examgoal.net/fly/@width/image/1l79egidm/a6690954-7aeb-421e-841b-1c4509718aab/ba67f6a0-24a6-11ed-8d2e-5f0df5271c2d/file-1l79egidn.png?format=png" data-orsrc="https://app-content.cdn.examgoal.net/image/1l79egidm/a66...
integer
jee-main-2022-online-25th-july-morning-shift
7,518
1l6m6g453
maths
permutations-and-combinations
number-of-permutations
<p>Let $$S$$ be the set of all passwords which are six to eight characters long, where each character is either an alphabet from $$\{A, B, C, D, E\}$$ or a number from $$\{1,2,3,4,5\}$$ with the repetition of characters allowed. If the number of passwords in $$S$$ whose at least one character is a number from $$\{1,2,3...
[]
null
7073
<p>If password is 6 character long, then</p> <p>Total number of ways having atleast one number $$ = {10^6} - {5^6}$$</p> <p>Similarly, if 7 character long $$ = {10^7} - {5^7}$$</p> <p>and if 8-character long $$ = {10^8} - {5^8}$$</p> <p>Number of password $$ = ({10^6} + {10^7} + {10^8}) - ({5^6} + {5^7} + {5^8})$$</p> ...
integer
jee-main-2022-online-28th-july-morning-shift
7,519
ldoan5f0
maths
permutations-and-combinations
number-of-permutations
If ${ }^{2 n+1} \mathrm{P}_{n-1}:{ }^{2 n-1} \mathrm{P}_{n}=11: 21$, <br/><br/>then $n^{2}+n+15$ is equal to :
[]
null
45
$\frac{\frac{(2 n+1) !}{(n+2) !}}{\frac{(2 n-1) !}{(n-1) !}}=\frac{11}{21}$ <br/><br/>$\frac{(2 n+1) 2 n}{(n+2)(n+1) n}=\frac{11}{21}$ <br/><br/>$84 n+42=11\left(n^{2}+3 n+2\right)$ <br/><br/>$11 n^{2}-51 n-20=0$ <br/><br/>$(n-5)(11 n+4)=0$ <br/><br/>$n=5, \frac{-4}{11}$ (Rejected $)$ <br/><br/>$n^{2}+n+15=45$
integer
jee-main-2023-online-31st-january-evening-shift
7,520
1ldom13ou
maths
permutations-and-combinations
number-of-permutations
<p>The value of $$\frac{1}{1 ! 50 !}+\frac{1}{3 ! 48 !}+\frac{1}{5 ! 46 !}+\ldots .+\frac{1}{49 ! 2 !}+\frac{1}{51 ! 1 !}$$ is :</p>
[{"identifier": "A", "content": "$$\\frac{2^{51}}{50 !}$$"}, {"identifier": "B", "content": "$$\\frac{2^{51}}{51 !}$$"}, {"identifier": "C", "content": "$$\\frac{2^{50}}{50 !}$$"}, {"identifier": "D", "content": "$$\\frac{2^{50}}{51 !}$$"}]
["D"]
null
$$ \begin{aligned} & \mathrm{S}=\frac{1}{1 ! 50 !}+\frac{1}{3 ! 48 !}+\frac{1}{5 ! 46 !}+\ldots \ldots+\frac{1}{49 ! 2 !}+\frac{1}{51 ! 1 !} \\\\ & =\frac{1}{51 !}\left(\frac{51 !}{1 ! 50 !}+\frac{51 !}{3 ! 48 !}+\frac{51 !}{5 ! 46 !}+\ldots . .+\frac{51 !}{49 ! 2 !}+\frac{51 !}{51 ! 0 !}\right) \\\\ & =\frac{1}{51 !}\...
mcq
jee-main-2023-online-1st-february-morning-shift
7,521
1ldoo8du5
maths
permutations-and-combinations
number-of-permutations
<p>The number of 3-digit numbers, that are divisible by either 2 or 3 but not divisible by 7, is ____________.</p>
[]
null
514
<img src="https://app-content.cdn.examgoal.net/fly/@width/image/1le9xbqbh/6a03e2bb-e7c5-4885-abb8-b77d1c53361f/0699bad0-af86-11ed-8a80-c79017866e24/file-1le9xbqbi.png?format=png" data-orsrc="https://app-content.cdn.examgoal.net/image/1le9xbqbh/6a03e2bb-e7c5-4885-abb8-b77d1c53361f/0699bad0-af86-11ed-8a80-c79017866e24/fi...
integer
jee-main-2023-online-1st-february-morning-shift
7,522
1ldseml3w
maths
permutations-and-combinations
number-of-permutations
<p>The letters of the word OUGHT are written in all possible ways and these words are arranged as in a dictionary, in a series. Then the serial number of the word TOUGH is :</p>
[{"identifier": "A", "content": "79"}, {"identifier": "B", "content": "84"}, {"identifier": "C", "content": "89"}, {"identifier": "D", "content": "86"}]
["C"]
null
<p>Lets arrange the letters of OUGHT in alphabetical order. <br/><br/>G, H, O, T, U</p> <br/>Words starting with <br/><br/>$$ \begin{aligned} & \mathrm{G}----\rightarrow 4 ! \\\\ & \mathrm{H}----\rightarrow 4 ! \\\\ & \mathrm{O}----\rightarrow 4 ! \end{aligned} $$ <br/><br/>$\mathrm{T} \,\mathrm{G}---\rightarrow 3$ ! ...
mcq
jee-main-2023-online-29th-january-evening-shift
7,524
1ldswzrar
maths
permutations-and-combinations
number-of-permutations
<p>Five digit numbers are formed using the digits 1, 2, 3, 5, 7 with repetitions and are written in descending order with serial numbers. For example, the number 77777 has serial number 1. Then the serial number of 35337 is ____________.</p>
[]
null
1436
<p>Descending order means from highest to lowest.</p> <p>$$\therefore$$ Descending order of digits 1, 2, 3, 5, 7 is = 7, 5, 3, 2, 1.</p> <p>(1) Number starts with 7 :</p> <p><img src="https://app-content.cdn.examgoal.net/fly/@width/image/1le2g13sg/30377b8c-aded-4085-8900-acce8af1dc3b/e75d6700-ab68-11ed-b566-111c81fc645...
integer
jee-main-2023-online-29th-january-morning-shift
7,525
1ldww37nt
maths
permutations-and-combinations
number-of-permutations
<p>The number of integers, greater than 7000 that can be formed, using the digits 3, 5, 6, 7, 8 without repetition is :</p>
[{"identifier": "A", "content": "48"}, {"identifier": "B", "content": "120"}, {"identifier": "C", "content": "168"}, {"identifier": "D", "content": "220"}]
["C"]
null
Four digit numbers greater than 7000 $=2 \times 4 \times 3 \times 2=48$<br/><br/> Five digit number $=5 !=120$<br/><br/> Total number greater than 7000 $=120+48=168$
mcq
jee-main-2023-online-24th-january-evening-shift
7,526
1lgow5dwx
maths
permutations-and-combinations
number-of-permutations
<p>All words, with or without meaning, are made using all the letters of the word MONDAY. These words are written as in a dictionary with serial numbers. The serial number of the word MONDAY is :</p>
[{"identifier": "A", "content": "324"}, {"identifier": "B", "content": "328"}, {"identifier": "C", "content": "326"}, {"identifier": "D", "content": "327"}]
["D"]
null
<p>The letters of &quot;MONDAY&quot; arranged in alphabetical order are: A, D, M, N, O, Y.</p> <ol> <li>Fix A as the first letter, we can arrange the remaining 5 letters in 5! ways = 120 ways.</li> <li>Fix D as the first letter, we can arrange the remaining 5 letters in 5! ways = 120 ways.</li> </ol> <p>So far, we hav...
mcq
jee-main-2023-online-13th-april-evening-shift
7,527
1lgsugvol
maths
permutations-and-combinations
number-of-permutations
<p>If the letters of the word MATHS are permuted and all possible words so formed are arranged as in a dictionary with serial numbers, then the serial number of the word THAMS is :</p>
[{"identifier": "A", "content": "103"}, {"identifier": "B", "content": "104"}, {"identifier": "C", "content": "102"}, {"identifier": "D", "content": "101"}]
["A"]
null
To solve this problem, we start by finding the number of permutations before we reach a word that begins with T. <br/><br/>We have 5 letters in the word MATHS. If we fix the first letter, there are 4! (=4$$ \times $$3$$ \times $$2$$ \times $$1=24) ways to arrange the remaining letters. <br/><br/>The letters before T...
mcq
jee-main-2023-online-11th-april-evening-shift
7,528
1lgvqlzes
maths
permutations-and-combinations
number-of-permutations
<p>The sum of all the four-digit numbers that can be formed using all the digits 2, 1, 2, 3 is equal to __________.</p>
[]
null
26664
We have, four digits are $2,1,2,3$. <br/><br/>Total numbers when 1 is at unit digit $=\frac{3 !}{2 !}=3$ <br/><br/>Total number when 2 is at unit digit $=3 !=6$ <br/><br/>Total numbers when 3 is at unit digit $=\frac{3 !}{2 !}=3$ <br/><br/>Sum of digits at unit place $=3 \times 1+6 \times 2+3 \times 3=24$ <br/><br/>$\t...
integer
jee-main-2023-online-10th-april-evening-shift
7,529
1lh2xtxhh
maths
permutations-and-combinations
number-of-permutations
<p> All the letters of the word PUBLIC are written in all possible orders and these words are written as in a dictionary with serial numbers. Then the serial number of the word PUBLIC is :</p>
[{"identifier": "A", "content": "578"}, {"identifier": "B", "content": "576"}, {"identifier": "C", "content": "580"}, {"identifier": "D", "content": "582"}]
["D"]
null
Given word is PUBLIC. <br/><br/>Alphabetical order of letters is BCILPU. So, number of words start with letter. <br/><br/>B - - - - is $5 !=120$ <br/><br/>C ---- is $5 !=120$ <br/><br/>I ----- is $5 !=120$ <br/><br/>$\mathrm{L}-----$ is $5 !=120$ <br/><br/>$\mathrm{PB}----$ is $4 !=24$ <br/><br/>$\mathrm{PC}----$ is ...
mcq
jee-main-2023-online-6th-april-evening-shift
7,530
jaoe38c1lse5y7d4
maths
permutations-and-combinations
number-of-permutations
<p>The total number of words (with or without meaning) that can be formed out of the letters of the word '<b>DISTRIBUTION</b>' taken four at a time, is equal to __________.</p>
[]
null
3734
<p>We have III, TT, D, S, R, B, U, O, N</p> <p>Number of words with selection (a, a, a, b)</p> <p>$$={ }^8 \mathrm{C}_1 \times \frac{4 !}{3 !}=32$$</p> <p>Number of words with selection (a, a, b, b)</p> <p>$$=\frac{4 !}{2 ! 2 !}=6$$</p> <p>Number of words with selection (a, a, b, c)</p> <p>$$={ }^2 \mathrm{C}_1 \times{...
integer
jee-main-2024-online-31st-january-morning-shift
7,531
jaoe38c1lsf0oh50
maths
permutations-and-combinations
number-of-permutations
<p>All the letters of the word "GTWENTY" are written in all possible ways with or without meaning and these words are written as in a dictionary. The serial number of the word "GTWENTY" is _________.</p>
[]
null
553
<p>Words starting with $$\mathrm{E}=360$$</p> <p>Words starting with $$\mathrm{GE=60}$$</p> <p>Words starting with $$\mathrm{GN=60}$$</p> <p>Words starting with $$\mathrm{GTE=24}$$</p> <p>Words starting with $$\mathrm{GTN=24}$$</p> <p>Words starting with $$\mathrm{GTT=24}$$</p> <p>GTWENTY $$=1$$</p> <p>Total $$=553$$</...
integer
jee-main-2024-online-29th-january-morning-shift
7,532
lv5gsk30
maths
permutations-and-combinations
number-of-permutations
<p>The number of 3-digit numbers, formed using the digits 2, 3, 4, 5 and 7, when the repetition of digits is not allowed, and which are not divisible by 3 , is equal to ________.</p>
[]
null
36
<p>To solve this problem, we need to find the number of 3-digit numbers formed using the digits 2, 3, 4, 5, and 7, with no repetition of digits allowed, and these numbers should not be divisible by 3. Let's break down the solution step-by-step:</p> <p>1. <strong>Calculating the total number of 3-digit numbers without ...
integer
jee-main-2024-online-8th-april-morning-shift
7,534
lv9s20f0
maths
permutations-and-combinations
number-of-permutations
<p>60 words can be made using all the letters of the word $$\mathrm{BHBJO}$$, with or without meaning. If these words are written as in a dictionary, then the $$50^{\text {th }}$$ word is:</p>
[{"identifier": "A", "content": "OBBJH"}, {"identifier": "B", "content": "HBBJO"}, {"identifier": "C", "content": "OBBHJ"}, {"identifier": "D", "content": "JBBOH"}]
["A"]
null
<p>To find the $$50^{\text{th}}$$ word formed by the letters of "BHBJO" as if listed in a dictionary, let's analyze the arrangement methodically. Given the letters are B, H, B, J, O, there are some repetitions with the letter B appearing twice.</p> <p>First, calculate the total number of permutations of these letters:...
mcq
jee-main-2024-online-5th-april-evening-shift
7,535
lvb294sf
maths
permutations-and-combinations
number-of-permutations
<p>If all the words with or without meaning made using all the letters of the word "NAGPUR" are arranged as in a dictionary, then the word at $$315^{\text {th }}$$ position in this arrangement is :</p>
[{"identifier": "A", "content": "NRAPUG\n"}, {"identifier": "B", "content": "NRAGUP\n"}, {"identifier": "C", "content": "NRAPGU\n"}, {"identifier": "D", "content": "NRAGPU"}]
["C"]
null
<p>NAGPUR</p> <p>Word at $$315^{\text {th }}$$ position</p> <p>$$\begin{aligned} & \text { A...... }=5!=120 \\ & \text { G....... }=5!=120 \\ & \text { NA..... }=4!=24 \\ & \text { NG..... }=4!=24 \\ & \text { NP..... }=4!=24 \end{aligned}$$</p> <p>..... Till 312 words</p> <p>$$313^{\text {th }} \text { word }=\text { ...
mcq
jee-main-2024-online-6th-april-evening-shift
7,536
ys2abeQH99za49tLBzsHL
maths
probability
bayes-theorem
A box 'A' contains $$2$$ white, $$3$$ red and $$2$$ black balls. Another box 'B' contains $$4$$ white, $$2$$ red and $$3$$ black balls. If two balls are drawn at random, without eplacement, from a randomly selected box and one ball turns out to be white while the other ball turns out to be red, then the probability th...
[{"identifier": "A", "content": "$${9 \\over {16}}$$ "}, {"identifier": "B", "content": "$${7 \\over {16}}$$"}, {"identifier": "C", "content": "$${9 \\over {32}}$$"}, {"identifier": "D", "content": "$${7 \\over {8}}$$"}]
["B"]
null
Probability of drawing a white ball and then a red ball <br><br>from bag B is given by $${{{}^4{C_1} \times {}^2{C_1}} \over {{}^9{C_2}}}$$ = $${2 \over 9}$$ <br><br>Probability of drawing a white ball and then a red ball <br><br>from bag A is given by $${{{}^2{C_1} \times {}^3{C_1}} \over {{}^7{C_2}}}$$ = $${2 \ov...
mcq
jee-main-2018-online-15th-april-morning-slot
7,537
ddcEu6sJsoUFV2yTjBjgy2xukewmw2ol
maths
probability
bayes-theorem
Box I contains 30 cards numbered 1 to 30 and Box II contains 20 cards numbered 31 to 50. A box is selected at random and a card is drawn from it. The number on the card is found to be a non-prime number. The probability that the card was drawn from Box I is :
[{"identifier": "A", "content": "$${8 \\over {17}}$$"}, {"identifier": "B", "content": "$${2 \\over 3}$$"}, {"identifier": "C", "content": "$${2 \\over 5}$$"}, {"identifier": "D", "content": "$${4 \\over {17}}$$"}]
["A"]
null
Let B<sub>1</sub> be the event where Box-I is selected. <br><br>And B<sub>2</sub> be the event where Box-II is selected. <br><br>P(B<sub>1</sub>) = P(B<sub>2</sub>) = $${1 \over 2}$$ <br><br>Let E be the event where selected card is non prime. <br><br>For B<sub>1</sub> : Prime numbers: {2, 3, 5, 7, 11, 13, 17, 19, 23, ...
mcq
jee-main-2020-online-2nd-september-morning-slot
7,538
RTeG7N1NMdtZ3ITnFI1klt88cer
maths
probability
bayes-theorem
In a group of 400 people, 160 are smokers and non-vegetarian; 100 are smokers and vegetarian and the remaining 140 are non-smokers and vegetarian. Their chances of getting a particular chest disorder are 35%, 20% and 10% respectively. A person is chosen from the group at random and is found to be suffering from the che...
[{"identifier": "A", "content": "$${{14} \\over {45}}$$"}, {"identifier": "B", "content": "$${{8} \\over {45}}$$"}, {"identifier": "C", "content": "$${{7} \\over {45}}$$"}, {"identifier": "D", "content": "$${{28} \\over {45}}$$"}]
["D"]
null
Consider following events<br><br>A : Person chosen is a smoker and non vegetarian.<br><br>B : Person chosen in a smoker and vegetarian.<br><br>C : Person chosen is a non-smoker and vegetarian.<br><br>E : Person chosen has a chest disorder<br><br>Given <br><br>$$P(A) = {{160} \over {400}}$$ <br><br>$$P(B) = {{100} \over...
mcq
jee-main-2021-online-25th-february-evening-slot
7,539
1l5c0v06l
maths
probability
bayes-theorem
<p>Bag A contains 2 white, 1 black and 3 red balls and bag B contains 3 black, 2 red and n white balls. One bag is chosen at random and 2 balls drawn from it at random, are found to be 1 red and 1 black. If the probability that both balls come from Bag A is $${6 \over {11}}$$, then n is equal to __________.</p>
[{"identifier": "A", "content": "13"}, {"identifier": "B", "content": "6"}, {"identifier": "C", "content": "4"}, {"identifier": "D", "content": "3"}]
["C"]
null
<img src="https://app-content.cdn.examgoal.net/fly/@width/image/1l8la6rik/8b350f4d-948a-4095-a004-5c8116776062/a60740c0-3efb-11ed-8e30-11b9f1cb84fb/file-1l8la6ril.png?format=png" data-orsrc="https://app-content.cdn.examgoal.net/image/1l8la6rik/8b350f4d-948a-4095-a004-5c8116776062/a60740c0-3efb-11ed-8e30-11b9f1cb84fb/fi...
mcq
jee-main-2022-online-24th-june-morning-shift
7,540
1l6rev2p3
maths
probability
bayes-theorem
<p>Bag I contains 3 red, 4 black and 3 white balls and Bag II contains 2 red, 5 black and 2 white balls. One ball is transferred from Bag I to Bag II and then a ball is drawn from Bag II. The ball so drawn is found to be black in colour. Then the probability, that the transferred ball is red, is :</p>
[{"identifier": "A", "content": "$$\\frac{4}{9}$$"}, {"identifier": "B", "content": "$$\\frac{5}{18}$$"}, {"identifier": "C", "content": "$$\\frac{1}{6}$$"}, {"identifier": "D", "content": "$$\\frac{3}{10}$$"}]
["B"]
null
Let $E \rightarrow$ Ball drawn from Bag II is black. <br/><br/> $E_{R} \rightarrow$ Bag I to Bag II red ball transferred. <br/><br/> $E_{B} \rightarrow$ Bag I to Bag II black ball transferred. <br/><br/> $E_{w} \rightarrow$ Bag I to Bag II white ball transferred. <br/><br/> $P\left(E_{R} / E\right)=\frac{P\left(E / E_{...
mcq
jee-main-2022-online-29th-july-evening-shift
7,541
1ldprftih
maths
probability
bayes-theorem
<p>A bag contains 6 balls. Two balls are drawn from it at random and both are found to be black. The probability that the bag contains at least 5 black balls is :</p>
[{"identifier": "A", "content": "$$\\frac{3}{7}$$"}, {"identifier": "B", "content": "$$\\frac{5}{6}$$"}, {"identifier": "C", "content": "$$\\frac{5}{7}$$"}, {"identifier": "D", "content": "$$\\frac{2}{7}$$"}]
["C"]
null
Let $E_{i} \rightarrow$ Bag have at least $i$ black balls <br/><br/>$E \rightarrow 2$ balls are drawn &amp; both black <br/><br/>$$ \begin{aligned} & \therefore P\left(\frac{E_{5} \text { or } E_{6}}{E}\right)=\frac{P\left(\frac{E}{E_{5}}\right)+P\left(\frac{E}{E_{6}}\right)}{\sum\limits_{i=1}^{6} P\left(\frac{E}{E_{...
mcq
jee-main-2023-online-31st-january-morning-shift
7,542
1ldwxvdwq
maths
probability
bayes-theorem
<p>Three urns A, B and C contain 4 red, 6 black; 5 red, 5 black; and $$\lambda$$ red, 4 black balls respectively. One of the urns is selected at random and a ball is drawn. If the ball drawn is red and the probability that it is drawn from urn C is 0.4 then the square of the length of the side of the largest equilatera...
[]
null
432
$E_{1}$ : Ball is drawn from urn $A(4 R+6 B)$ <br><br> $E_{2}:$ Ball is drawn from urn $B(5 R+5 B)$ <br><br> $E_{3}$ : Ball is drawn from urn $C(\lambda R+4 B)$ <br><br> $A \rightarrow$ Ball drawn is red. <br><br> Required probability $=P\left(\frac{E_{3}}{A}\right)$ <br><br> $=\frac{\frac{1}{3} \times \frac{\lambda}{\...
integer
jee-main-2023-online-24th-january-evening-shift
7,543
1lsg4n319
maths
probability
bayes-theorem
<p>Bag A contains 3 white, 7 red balls and Bag B contains 3 white, 2 red balls. One bag is selected at random and a ball is drawn from it. The probability of drawing the ball from the bag A, if the ball drawn is white, is</p>
[{"identifier": "A", "content": "1/4"}, {"identifier": "B", "content": "1/3"}, {"identifier": "C", "content": "3/10"}, {"identifier": "D", "content": "1/9"}]
["B"]
null
<p><img src="https://app-content.cdn.examgoal.net/fly/@width/image/6y3zli1lsoxmoxg/bddbd042-adc7-47f2-8492-6edfb8c4f19c/00793740-ccf2-11ee-a330-494dca5e9a63/file-6y3zli1lsoxmoxh.png?format=png" data-orsrc="https://app-content.cdn.examgoal.net/image/6y3zli1lsoxmoxg/bddbd042-adc7-47f2-8492-6edfb8c4f19c/00793740-ccf2-11ee...
mcq
jee-main-2024-online-30th-january-evening-shift
7,544
lv3ve61j
maths
probability
bayes-theorem
<p>There are three bags $$X, Y$$ and $$Z$$. Bag $$X$$ contains 5 one-rupee coins and 4 five-rupee coins; Bag $$Y$$ contains 4 one-rupee coins and 5 five-rupee coins and Bag $$Z$$ contains 3 one-rupee coins and 6 five-rupee coins. A bag is selected at random and a coin drawn from it at random is found to be a one-rupee ...
[{"identifier": "A", "content": "$$\\frac{1}{2}$$\n"}, {"identifier": "B", "content": "$$\\frac{1}{3}$$\n"}, {"identifier": "C", "content": "$$\\frac{5}{12}$$\n"}, {"identifier": "D", "content": "$$\\frac{1}{4}$$"}]
["B"]
null
<p>To solve this problem, we use Bayes' theorem. Let's define the events:</p> <ul> <li>$$X$$: Selecting bag $$X$$</li> <li>$$Y$$: Selecting bag $$Y$$</li> <li>$$Z$$: Selecting bag $$Z$$</li> <li>$$A$$: Drawing a one-rupee coin</li> </ul> <p>We are given that a bag is selected at random, so the probabilities for ...
mcq
jee-main-2024-online-8th-april-evening-shift
7,546
lvc586ak
maths
probability
bayes-theorem
<p>A company has two plants $$A$$ and $$B$$ to manufacture motorcycles. $$60 \%$$ motorcycles are manufactured at plant $$A$$ and the remaining are manufactured at plant $$B .80 \%$$ of the motorcycles manufactured at plant $$A$$ are rated of the standard quality, while $$90 \%$$ of the motorcycles manufactured at plan...
[{"identifier": "A", "content": "54"}, {"identifier": "B", "content": "66"}, {"identifier": "C", "content": "56"}, {"identifier": "D", "content": "64"}]
["A"]
null
<p>$$\begin{aligned} & P(\text { standard automobile from } A)=\frac{6}{10} \times \frac{8}{10}=\frac{12}{25} \\ & P(\text { standard automobile from } B)=\frac{4}{10} \times \frac{9}{10}=\frac{9}{25} \end{aligned}$$</p> <p>$$\begin{aligned} & \text { Required Probability } \frac{\frac{9}{25}}{\frac{12}{25}+\frac{9}{25...
mcq
jee-main-2024-online-6th-april-morning-shift
7,547
byM0olMAPi99wdnA
maths
probability
binomial-distribution
A dice is tossed $$5$$ times. Getting an odd number is considered a success. Then the variance of distribution of success is :
[{"identifier": "A", "content": "$$8/3$$"}, {"identifier": "B", "content": "$$3/8$$"}, {"identifier": "C", "content": "$$4/5$$ "}, {"identifier": "D", "content": "$$5/4$$"}]
["D"]
null
Total no of trials = 5 <br>$$\therefore$$ n = 5 <br>Odd no possibe are = {1, 3, 5} =3 <br>Sample space = {1, 2, 3, 4, 5, 6} = 6 <br><br>Probablity of getting odd number = $${3 \over 6}$$ = $${1 \over 2}$$ <br>$$\therefore$$ p = $${1 \over 2}$$ <br><br>Formula for variance = npq <br>where q = 1 - p = 1 - $${1 \over 2}$$...
mcq
aieee-2002
7,548
KSCoYtIeFC6mdWAN
maths
probability
binomial-distribution
The mean and variance of a random variable $$X$$ having binomial distribution are $$4$$ and $$2$$ respectively, then $$P(X=1)$$ is :
[{"identifier": "A", "content": "$${1 \\over 4}$$ "}, {"identifier": "B", "content": "$${1 \\over 32}$$"}, {"identifier": "C", "content": "$${1 \\over 16}$$"}, {"identifier": "D", "content": "$${1 \\over 8}$$"}]
["B"]
null
Mean = $$np$$ = 4 <br>Variance = $$npq$$ = 2 <br><br>$$ \Rightarrow 4 \times q$$ = 2 <br>$$ \Rightarrow$$ $$q$$ = $${1 \over 2}$$ <br>p = 1 - q = 1 - $${1 \over 2}$$ = $${1 \over 2}$$ <br>n = 8 <br><br>Now P(X = 1) = $${}^8{C_1}{\left( {{1 \over 2}} \right)^1}{\left( {{1 \over 2}} \right)^{8 - 1}}$$ <br>&nbsp;&nbsp;&nb...
mcq
aieee-2003
7,549
WwUXVwpKwqJWZr3N
maths
probability
binomial-distribution
The mean and the variance of a binomial distribution are $$4$$ and $$2$$ respectively. Then the probability of $$2$$ successes is :
[{"identifier": "A", "content": "$${28 \\over 256}$$"}, {"identifier": "B", "content": "$${219 \\over 256}$$"}, {"identifier": "C", "content": "$${128 \\over 256}$$"}, {"identifier": "D", "content": "$${37 \\over 256}$$"}]
["A"]
null
<p>Given that mean = 4 = np = 4 and variance = 2</p> <p>npq = 2 $$\Rightarrow$$ 4q = 2</p> <p>$$ \Rightarrow q = {1 \over 2}$$</p> <p>$$\therefore$$ $$p = 1 - q = 1 - {1 \over 2} = {1 \over 2}$$</p> <p>Also, n = 8</p> <p>Probability of 2 successes $$ = P(X = 2) = {}^8{C_2}{p^2}{q^6}$$</p> <p>$$ = {{8!} \over {2! \times...
mcq
aieee-2004
7,550
uWKlDoLk0I45E7uG
maths
probability
binomial-distribution
In a binomial distribution $$B\left( {n,p = {1 \over 4}} \right),$$ if the probability of at least one success is greater than or equal to $${9 \over {10}},$$ then $$n$$ is greater than :
[{"identifier": "A", "content": "$${1 \\over {\\log _{10}^4 + \\log _{10}^3}}$$"}, {"identifier": "B", "content": "$${9 \\over {\\log _{10}^4 - \\log _{10}^3}}$$"}, {"identifier": "C", "content": "$${4 \\over {\\log _{10}^4 - \\log _{10}^3}}$$"}, {"identifier": "D", "content": "$${1 \\over {\\log _{10}^4 - \\log _{10}^...
["D"]
null
Given that, no of trials = n <br>Probability of success (p) = $${{1 \over 4}}$$ <br>$$\therefore$$ Probability of no success = 1 - $${{1 \over 4}}$$ = $${{3 \over 4}}$$ <br><br>As we know, probability of at least one success = 1 - probability of no success <br><br>$$\therefore$$ According to the question, <br><br>1 - (...
mcq
aieee-2009
7,552
OE21asjIebiZi6xf
maths
probability
binomial-distribution
Consider $$5$$ independent Bernoulli's trials each with probability of success $$p.$$ If the probability of at least one failure is greater than or equal to $${{31} \over 32},$$ then $$p$$ lies in the interval :
[{"identifier": "A", "content": "$$\\left( {{3 \\over 4},{{11} \\over {12}}} \\right]$$ "}, {"identifier": "B", "content": "$$\\left[ {0,{1 \\over 2}} \\right]$$ "}, {"identifier": "C", "content": "$$\\left( {{11 \\over 12},1} \\right]$$"}, {"identifier": "D", "content": "$$\\left( {{1 \\over 2},{{3} \\over {4}}} \\rig...
["B"]
null
Here is 5 trials. <br>So according to Bernoulli trial n = 5 <br><br>P( at least one failure) = 1 - P( no failure) <br><br>According to question, <br>1 - P( no failure) $$ \ge {{31} \over {32}}$$ <br><br>$$ \Rightarrow $$ 1 - P( x = 5 ) $$ \ge {{31} \over {32}}$$ <br><br>[<b>Note:</b> no failure = all success] <br><br>$...
mcq
aieee-2011
7,553
6W0qksJnJVRp3xfN
maths
probability
binomial-distribution
A multiple choice examination has $$5$$ questions. Each question has three alternative answers of which exactly one is correct. The probability that a student will get $$4$$ or more correct answers just by guessing is :
[{"identifier": "A", "content": "$${{17} \\over {{3^5}}}$$ "}, {"identifier": "B", "content": "$${{13} \\over {{3^5}}}$$"}, {"identifier": "C", "content": "$${{11} \\over {{3^5}}}$$"}, {"identifier": "D", "content": "$${{10} \\over {{3^5}}}$$"}]
["C"]
null
Each question has 3 alternative and exactly one is correct. <br><br>$$\therefore$$ Probability of giving correct answer P(correct) = $${1 \over 3}$$ <br><br>$$\therefore$$ Probability of giving wrong answer P(wrong) = $${2 \over 3}$$ <br><br>Here student give 4 or more correct answer. <br><br>$$\therefore$$ Student giv...
mcq
jee-main-2013-offline
7,554
fPr4yNo79AsCQj24OgUaE
maths
probability
binomial-distribution
An experiment succeeds twice as often as it fails. The probability of at least 5 successes in the six trials of this experiment is :
[{"identifier": "A", "content": "$${{240} \\over {729}}$$ "}, {"identifier": "B", "content": "$${{192} \\over {729}}$$"}, {"identifier": "C", "content": "$${{256} \\over {729}}$$"}, {"identifier": "D", "content": "$${{496} \\over {729}}$$"}]
["C"]
null
Probability of fail, P(F) = p <br><br>$$ \therefore $$&nbsp;&nbsp;&nbsp;Probability of success, P(S) = 2p <br><br>We know, <br><br>p + 2Pp = 1 <br><br>$$ \Rightarrow $$&nbsp;&nbsp;&nbsp;p = $${1 \over 3}$$ <br><br>$$ \therefore $$&nbsp;&nbsp;&nbsp;Now, probability of at least 5 success in 6 trials, <br><br>P(x $$ \ge ...
mcq
jee-main-2016-online-10th-april-morning-slot
7,555
TNLBuSQYBYqruPcC
maths
probability
binomial-distribution
A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is :
[{"identifier": "A", "content": "6"}, {"identifier": "B", "content": "4"}, {"identifier": "C", "content": "$${6 \\over {25}}$$"}, {"identifier": "D", "content": "$${{12} \\over 5}$$"}]
["D"]
null
We can apply binomial probability distribution <br><br>n = 10 <br><br>p = Probability of drawing a green ball = $${{15} \over {25}}$$ = $${3 \over 5}$$ <br><br>Also q = 1 - $${3 \over 5}$$ = $${2 \over 5}$$ <br><br>Variance = npq <br><br>= $$10 \times {3 \over 5} \times {2 \over 5}$$ = $${{12} \over 5}$$
mcq
jee-main-2017-offline
7,556
dNyf7SQZWaNvnOFNKi3rsa0w2w9jxb0q6m7
maths
probability
binomial-distribution
For an initial screening of an admission test, a candidate is given fifty problems to solve. If the probability that the candidate solve any problem is $${4 \over 5}$$ , then the probability that he is unable to solve less than two problems is :
[{"identifier": "A", "content": "$${{164} \\over {25}}{\\left( {{1 \\over 5}} \\right)^{48}}$$"}, {"identifier": "B", "content": "$${{316} \\over {25}}{\\left( {{4 \\over 5}} \\right)^{48}}$$"}, {"identifier": "C", "content": "$${{201} \\over 5}{\\left( {{1 \\over 5}} \\right)^{49}}$$"}, {"identifier": "D", "content": ...
["D"]
null
There are 50 questions in an exam.<br><br> So Probability of each question to be correct is p = $${4 \over 5}$$<br><br> and also probability of each question to be incorrect is q = $${1 \over 5}$$<br><br> Let Y is the number of correct question in 50 questions, hence required probability is <br><br> $${\left( {{4 \over...
mcq
jee-main-2019-online-12th-april-evening-slot
7,558
y42Fg1dEZL6zPE14iO3rsa0w2w9jx66ep25
maths
probability
binomial-distribution
Let a random variable X have a binomial distribution with mean 8 and variance 4. If $$P\left( {X \le 2} \right) = {k \over {{2^{16}}}}$$, then k is equal to :
[{"identifier": "A", "content": "17"}, {"identifier": "B", "content": "1"}, {"identifier": "C", "content": "137"}, {"identifier": "D", "content": "121"}]
["C"]
null
Let number of trials be n and probability of success = p, probability of failure = q<br><br> Given np = 8, npq = 4<br><br> $$ \Rightarrow $$ q = $${1 \over 2}$$, p = $${1 \over 2}$$, n = 16 (as p + q = 1)<br><br> p$$\left( {x \le 2} \right)$$ = $${{{}^{16}{C_0} + {}^{16}{C_1} + {}^{16}{C_2}} \over {{2^{16}}}} = {{1 + 1...
mcq
jee-main-2019-online-12th-april-morning-slot
7,559
8LM5BOab51jC57AsuYgDh
maths
probability
binomial-distribution
A bag contains 30 white balls and 10 red balls. 16 balls are drawn one by one randomly from the bag with replacement. If X be the number of white balls drawn, then $$\left( {{{mean\,\,of\,X} \over {s\tan dard\,\,deviation\,\,of\,X}}} \right)$$ is equal to :
[{"identifier": "A", "content": "4"}, {"identifier": "B", "content": "$$3\\sqrt 2 $$"}, {"identifier": "C", "content": "$${{4\\sqrt 3 } \\over 3}$$"}, {"identifier": "D", "content": "$$4\\sqrt 3 $$"}]
["D"]
null
p (probability of getting white ball) = $${{30} \over {40}}$$ <br><br>q = $${1 \over 4}$$ and n = 16 <br><br>mean = np = 16.$${3 \over 4}$$ = 12 <br><br>and standard diviation <br><br>= $$\sqrt {npq} $$ = $$\sqrt {16.{3 \over 4}.{1 \over 4}} = \sqrt 3 $$<br><br> $$ \because $$ $$mean \over standard\,deviation$$ = $$12...
mcq
jee-main-2019-online-11th-january-evening-slot
7,560
sLnGz2MXngSYJtUcmwWgT
maths
probability
binomial-distribution
Two cards are drawn successively with replacement from a well-shuffled deck of 52 cards. Let X denote the random variable of number of aces obtained in the two drawn cards. Then P(X = 1) + P (X = 2) equals :
[{"identifier": "A", "content": "$$25 \\over 169$$"}, {"identifier": "B", "content": "$$49\\over 169$$"}, {"identifier": "C", "content": "$$24 \\over 169$$"}, {"identifier": "D", "content": "$$52 \\over 169$$"}]
["A"]
null
P (X = 1) means out of two drawn cards one card is ace. <br><br>and P(X = 2) means both the drawn cards are ace. <br><br>$$ \therefore $$&nbsp;&nbsp;P(X = 1) = first card is ace or 2nd card is ace. <br><br>= A _ $$+$$ _ A <br><br>= $${4 \over {52}} \times {{48} \over {52}} + {{48} \over {52}} \times {4 \over {52}}$$ <...
mcq
jee-main-2019-online-9th-january-morning-slot
7,561
2nkSMMiE7kPpEjjIP47k9k2k5filgzm
maths
probability
binomial-distribution
In a workshop, there are five machines and the probability of any one of them to be out of service on a day is $${{1 \over 4}}$$ . If the probability that at most two machines will be out of service on the same day is $${\left( {{3 \over 4}} \right)^3}k$$, then k is equal to :
[{"identifier": "A", "content": "$${{{17} \\over 4}}$$"}, {"identifier": "B", "content": "$${{{17} \\over 2}}$$"}, {"identifier": "C", "content": "$${{{17} \\over 8}}$$"}, {"identifier": "D", "content": "4"}]
["C"]
null
Probablity of at most two machines will be out of service = $${\left( {{3 \over 4}} \right)^3}k$$ <br><br>$$ \Rightarrow $$ <sup>5</sup>C<sub>0</sub>$${\left( {{3 \over 4}} \right)^5}$$ + <sup>5</sup>C<sub>1</sub>$$\left( {{1 \over 4}} \right){\left( {{3 \over 4}} \right)^5}$$ + <sup>5</sup>C<sub>2</sub>$${\left( {{1 \...
mcq
jee-main-2020-online-7th-january-evening-slot
7,562
ypdvxtIllDnLKrAoI3jgy2xukfqfwl3g
maths
probability
binomial-distribution
In a bombing attack, there is 50% chance that a bomb will hit the target. Atleast two independent hits are required to destroy the target completely. Then the minimum number of bombs, that must be dropped to ensure that there is at least 99% chance of completely destroying the target, is __________.
[]
null
11
Let n is total no. of bombs being dropped <br><br>at least 2 bombs should hit. <br><br>P(x &gt; 2) $$ \ge $$ 0.99 <br><br>$$ \Rightarrow $$ 1 - p(x &lt; 2) $$ \ge $$ 0.99 <br><br>$$ \Rightarrow $$ 1 - (p(x = 0) + p(x = 1)) $$ \ge $$ 0.99 <br><br>$$ \Rightarrow $$ 1 - <sup>n</sup>C<sub>0</sub>$${\left( {{1 \over 2}} \ri...
integer
jee-main-2020-online-5th-september-evening-slot
7,563
wcKeZHloIi9ghYWsTA1klrhaah4
maths
probability
binomial-distribution
An ordinary dice is rolled for a certain number of times. If the probability of getting an odd number 2 times is equal to the probability of getting an even number 3 times, then the probability of getting an odd number for odd number of times is :
[{"identifier": "A", "content": "$${5 \\over {36}}$$"}, {"identifier": "B", "content": "$${3 \\over {16}}$$"}, {"identifier": "C", "content": "$${1 \\over 2}$$"}, {"identifier": "D", "content": "$${1 \\over {32}}$$"}]
["C"]
null
P(odd no. twice) = P(even no. thrice)<br><br>$$ \Rightarrow {}^n{C_2}{\left( {{1 \over 2}} \right)^n} = {}^n{C_3}{\left( {{1 \over 2}} \right)^n} \Rightarrow n = 5$$<br><br>Success is getting an odd number then P(odd successes) = P(1) + P(3) + P(5)<br><br>$$ = {}^5{C_1}{\left( {{1 \over 2}} \right)^5} + {}^5{C_3}{\left...
mcq
jee-main-2021-online-24th-february-morning-slot
7,564
1krxij6cm
maths
probability
binomial-distribution
A student appeared in an examination consisting of 8 true-false type questions. The student guesses the answers with equal probability. the smallest value of n, so that the probability of guessing at least 'n' correct answers is less than $${1 \over 2}$$, is :
[{"identifier": "A", "content": "5"}, {"identifier": "B", "content": "6"}, {"identifier": "C", "content": "3"}, {"identifier": "D", "content": "4"}]
["A"]
null
$$P(E) &lt; {1 \over 2}$$<br><br>$$ \Rightarrow \sum\limits_{r = n}^8 {{}^8{C_r}} {\left( {{1 \over 2}} \right)^{8 - r}}{\left( {{1 \over 2}} \right)^r} &lt; {1 \over 2}$$<br><br>$$ \Rightarrow \sum\limits_{r = n}^8 {{}^8{C_r}} {\left( {{1 \over 2}} \right)^8} &lt; {1 \over 2}$$<br><br>$$ \Rightarrow {}^8{C_n} + {}^8{C...
mcq
jee-main-2021-online-27th-july-evening-shift
7,567
1ktfz7m08
maths
probability
binomial-distribution
Each of the persons A and B independently tosses three fair coins. The probability that both of them get the same number of heads is :
[{"identifier": "A", "content": "$${1 \\over 8}$$"}, {"identifier": "B", "content": "$${5 \\over 8}$$"}, {"identifier": "C", "content": "$${5 \\over 16}$$"}, {"identifier": "D", "content": "1"}]
["C"]
null
<p>Let x be the number of heads obtained by A, and y be the number of heads obtained by B.</p> <p>Note that x and y are binomial variable with parameters n = 3 and p = $${1 \over 2}$$</p> <p>$$\therefore$$ Probability that both A and B obtained the same number of heads is</p> <p>$$ = P(x = 0)\,.\,P(y = 0) + P(x = 1)\,....
mcq
jee-main-2021-online-27th-august-evening-shift
7,568
1l57op7rj
maths
probability
binomial-distribution
<p>Let X be a random variable having binomial distribution B(7, p). If P(X = 3) = 5P(x = 4), then the sum of the mean and the variance of X is :</p>
[{"identifier": "A", "content": "$${105 \\over {16}}$$"}, {"identifier": "B", "content": "$${7\\over {16}}$$"}, {"identifier": "C", "content": "$${77\\over {36}}$$"}, {"identifier": "D", "content": "$${49\\over {16}}$$"}]
["C"]
null
<p>Given P(X = 3) = 5P(X = 4) and n = 7</p> <p>$$ \Rightarrow {}^7{C_3}{p^3}{q^4} = 5\,.\, \Rightarrow {}^7{C_4}{p^4}{q^3}$$</p> <p>$$ \Rightarrow q = 5p$$ and also $$p + q = 1$$</p> <p>$$ \Rightarrow p = {1 \over 6}$$ and $$q = {5 \over 6}$$</p> <p>Mean $$ = {7 \over 6}$$ and variance $$ = {{35} \over {36}}$$</p> <p>M...
mcq
jee-main-2022-online-27th-june-morning-shift
7,569
1l58a4o04
maths
probability
binomial-distribution
<p>Let a biased coin be tossed 5 times. If the probability of getting 4 heads is equal to the probability of getting 5 heads, then the probability of getting atmost two heads is :</p>
[{"identifier": "A", "content": "$${{275} \\over {{6^5}}}$$"}, {"identifier": "B", "content": "$${{36} \\over {{5^4}}}$$"}, {"identifier": "C", "content": "$${{181} \\over {{5^5}}}$$"}, {"identifier": "D", "content": "$${{46} \\over {{6^4}}}$$"}]
["D"]
null
<p>Coin is tossed 5 times, so n = 5</p> <p>Let, p = probability of getting heads</p> <p>q = probability of getting tails.</p> <p>$$\therefore$$ p + q = 1 ...... (1)</p> <p>$$\therefore$$ Probability of getting 4 heads</p> <p>= <sup>5</sup>C<sub>4</sub> . p<sup>4</sup> . q</p> <p>And probability of getting 5 heads</p> <...
mcq
jee-main-2022-online-26th-june-morning-shift
7,570