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In the year 2009, there is a property that rearranging the digits of the number 2009 cannot yield a smaller four-digit number (numbers do not start with zero). In what subsequent year does this property first repeat again?
2022
0.125
7,741.625
5,818.5
8,016.357143
Calculate the value of $(2345 + 3452 + 4523 + 5234) \times 2$.
31108
0.4375
1,861.3125
2,652.142857
1,246.222222
Find the 6-digit repetend in the decimal representation of $\frac{7}{29}$.
241379
0.375
7,417.1875
6,364.333333
8,048.9
Joey and his five brothers are ages $3$, $5$, $7$, $9$, $11$, and $13$. One afternoon two of his brothers whose ages sum to $16$ went to the movies, two brothers younger than $10$ went to play baseball, and Joey and the $5$-year-old stayed home. How old is Joey?
11
1. **Identify the ages of Joey's brothers and the conditions given:** - The ages of the brothers are $3, 5, 7, 9, 11, 13$. - Two brothers whose ages sum to $16$ went to the movies. - Two brothers younger than $10$ went to play baseball. - Joey and the $5$-year-old stayed home. 2. **Determine the pairs of b...
0.5625
6,054.4375
4,548.444444
7,990.714286
The average age of five children is 6 years old. Each child is a different age and there is a difference of two years in the ages of any two consecutive children. In years, how old is the oldest child?
10
1
1,737.125
1,737.125
-1
An up-right path between two lattice points $P$ and $Q$ is a path from $P$ to $Q$ that takes steps of 1 unit either up or to the right. A lattice point $(x, y)$ with $0 \leq x, y \leq 5$ is chosen uniformly at random. Compute the expected number of up-right paths from $(0,0)$ to $(5,5)$ not passing through $(x, y)$
175
For a lattice point $(x, y)$, let $F(x, y)$ denote the number of up-right paths from $(0,0)$ to $(5,5)$ that don't pass through $(x, y)$, and let $$S=\sum_{0 \leq x \leq 5} \sum_{0 \leq y \leq 5} F(x, y)$$ Our answer is $\frac{S}{36}$, as there are 36 lattice points $(x, y)$ with $0 \leq x, y \leq 5$. Notice that the n...
0.0625
8,036.625
8,005
8,038.733333
Find the area of quadrilateral \(ABCD\) if \(AB = BC = 3\sqrt{3}\), \(AD = DC = \sqrt{13}\), and vertex \(D\) lies on a circle of radius 2 inscribed in the angle \(ABC\), where \(\angle ABC = 60^\circ\).
3\sqrt{3}
0.0625
8,192
8,192
8,192
A certain model of hybrid car travels from point $A$ to point $B$ with a fuel cost of $76$ yuan, and with an electricity cost of $26 yuan. It is known that for every kilometer traveled, the fuel cost is $0.5$ yuan more than the electricity cost. $(1)$ Find the cost of traveling one kilometer using electricity only. ...
74
0.25
7,006.4375
4,758.5
7,755.75
What is the area, in square units, of triangle $ABC$? [asy] unitsize(0.15inch); path X = (-6.5, 0)--(5.5, 0); path Y = (0, -3.5)--(0, 7.5); draw(X); draw(Y); for(int n=-6; n <= 5; ++n) if( n != 0 ) draw( (n,0.25)--(n,-0.25) ); for(int n=-3; n <= 7; ++n) if( n != 0 ) draw( (0.25,n)--(-0.25,n) ); pair A = (-4,3); pair ...
19
0.875
3,718
3,078.857143
8,192
The matrix $\mathbf{A} = \begin{pmatrix} 2 & 3 \\ 5 & d \end{pmatrix}$ satisfies \[\mathbf{A}^{-1} = k \mathbf{A}\]for some constant $k.$ Enter the ordered pair $(d,k).$
\left( -2, \frac{1}{19} \right)
0.9375
3,092.875
2,752.933333
8,192
Olga Ivanovna, the homeroom teacher of class 5B, is organizing a "Mathematical Ballet". She wants to arrange the boys and girls so that exactly 2 boys are at a distance of 5 meters from each girl. What is the maximum number of girls that can participate in the ballet if it is known that 5 boys are participating?
20
0.375
7,263.5
6,164.666667
7,922.8
To make pizza dough, Luca mixes 50 mL of milk for every 250 mL of flour. How many mL of milk does he mix with 750 mL of flour?
150
0.75
700.125
757.583333
527.75
Harry and Terry are each told to calculate $8-(2+5)$. Harry gets the correct answer. Terry ignores the parentheses and calculates $8-2+5$. If Harry's answer is $H$ and Terry's answer is $T$, what is $H-T$?
-10
1. **Calculate Harry's Answer ($H$):** Harry follows the correct order of operations (PEMDAS/BODMAS), which prioritizes parentheses first. Thus, he calculates: \[ H = 8 - (2 + 5) = 8 - 7 = 1 \] 2. **Calculate Terry's Answer ($T$):** Terry ignores the parentheses and calculates each operation from left t...
1
1,089.6875
1,089.6875
-1
The jury, when preparing versions of the district math olympiad problems for grades $7, 8, 9, 10, 11$, aims to ensure that each version for each grade contains exactly 7 problems, of which exactly 4 do not appear in any other version. What is the maximum number of problems that can be included in the olympiad?
27
0
7,215.625
-1
7,215.625
Let $x,$ $y,$ and $z$ be positive real numbers such that $xyz = 1.$ Find the minimum value of \[(x + 2y)(y + 2z)(xz + 1).\]
16
0.0625
8,130.9375
7,215
8,192
The positive integers $m$ and $n$ satisfy $8m + 9n = mn + 6$. Find the maximum value of $m$.
75
0.75
4,843.5
3,727.333333
8,192
Tim's quiz scores were 85, 87, 92, 94, 78, and 96. Calculate his mean score and find the range of his scores.
18
0.75
441.75
443.333333
437
A class leader is planning to invite graduates from the class of 2016 to give speeches. Out of 8 people, labeled A, B, ..., H, the leader wants to select 4 to speak. The conditions are: (1) at least one of A and B must participate; (2) if both A and B participate, there must be exactly one person speaking between them....
1080
0.0625
7,774.1875
5,266
7,941.4
A circle passes through the vertices $K$ and $P$ of triangle $KPM$ and intersects its sides $KM$ and $PM$ at points $F$ and $B$, respectively. Given that $K F : F M = 3 : 1$ and $P B : B M = 6 : 5$, find $K P$ given that $B F = \sqrt{15}$.
2 \sqrt{33}
0
8,192
-1
8,192
When 1524 shi of rice is mixed with an unknown amount of wheat, and in a sample of 254 grains, 28 are wheat grains, calculate the estimated amount of wheat mixed with this batch of rice.
168
0.125
5,698.1875
2,385.5
6,171.428571
Medians $\overline{DP}$ and $\overline{EQ}$ of $\triangle DEF$ intersect at an angle of $60^\circ$. If $DP = 21$ and $EQ = 27$, determine the length of side $DE$.
2\sqrt{67}
0.4375
6,365.125
4,016.285714
8,192
Given that \(\triangle ABC\) has sides \(a\), \(b\), and \(c\) corresponding to angles \(A\), \(B\), and \(C\) respectively, and knowing that \(a + b + c = 16\), find the value of \(b^2 \cos^2 \frac{C}{2} + c^2 \cos^2 \frac{B}{2} + 2bc \cos \frac{B}{2} \cos \frac{C}{2} \sin \frac{A}{2}\).
64
0.1875
7,557.375
4,807.333333
8,192
In the hexagonal pyramid $(P-ABCDEF)$, the base is a regular hexagon with side length $\sqrt{2}$, $PA=2$ and is perpendicular to the base. Find the volume of the circumscribed sphere of the hexagonal pyramid.
4\sqrt{3}\pi
0.1875
5,489.875
6,365.333333
5,287.846154
Each of $a, b$ and $c$ is equal to a number from the list $3^{1}, 3^{2}, 3^{3}, 3^{4}, 3^{5}, 3^{6}, 3^{7}, 3^{8}$. There are $N$ triples $(a, b, c)$ with $a \leq b \leq c$ for which each of $\frac{ab}{c}, \frac{ac}{b}$ and $\frac{bc}{a}$ is equal to an integer. What is the value of $N$?
86
We write $a=3^{r}, b=3^{s}$ and $c=3^{t}$ where each of $r, s, t$ is between 1 and 8, inclusive. Since $a \leq b \leq c$, then $r \leq s \leq t$. Next, we note that $\frac{ab}{c}=\frac{3^{r} 3^{s}}{3^{t}}=3^{r+s-t}$, $\frac{ac}{b}=\frac{3^{r} 3^{t}}{3^{s}}=3^{r+t-s}$, and $\frac{bc}{a}=\frac{3^{s} 3^{t}}{3^{r}}=3^{s+t-...
0.1875
7,991.5
7,122.666667
8,192
In a classroom, 34 students are seated in 5 rows of 7 chairs. The place at the center of the room is unoccupied. A teacher decides to reassign the seats such that each student will occupy a chair adjacent to his/her present one (i.e. move one desk forward, back, left or right). In how many ways can this reassignment be...
0
Color the chairs red and black in checkerboard fashion, with the center chair black. Then all 18 red chairs are initially occupied. Also notice that adjacent chairs have different colors. It follows that we need 18 black chairs to accommodate the reassignment, but there are only 17 of them. Thus, the answer is 0.
0.4375
7,472.0625
6,685.571429
8,083.777778
The maximum value of the function $f(x) = \frac{\frac{1}{6} \cdot (-1)^{1+ C_{2x}^{x}} \cdot A_{x+2}^{5}}{1+ C_{3}^{2} + C_{4}^{2} + \ldots + C_{x-1}^{2}}$ ($x \in \mathbb{N}$) is ______.
-20
0
8,117.1875
-1
8,117.1875
Express the given data "$20$ nanoseconds" in scientific notation.
2 \times 10^{-8}
0.75
368.875
352.25
418.75
Simplify the expression $\dfrac{45}{28} \cdot \dfrac{49}{75} \cdot \dfrac{100}{63}$.
\frac{5}{3}
0.8125
4,483.9375
3,936.769231
6,855
Given that $x \in (1,5)$, find the minimum value of the function $y= \frac{2}{x-1}+ \frac{1}{5-x}$.
\frac{3+2 \sqrt{2}}{4}
0
4,725.5
-1
4,725.5
Find the number of different complex numbers $z$ with the properties that $|z|=1$ and $z^{6!}-z^{5!}$ is a real number.
1440
0.0625
8,192
8,192
8,192
A standard deck of cards has 52 cards divided into 4 suits, each of which has 13 cards. Two of the suits ($\heartsuit$ and $\diamondsuit$, called `hearts' and `diamonds') are red, the other two ($\spadesuit$ and $\clubsuit$, called `spades' and `clubs') are black. The cards in the deck are placed in random order (usu...
\frac{25}{102}
1
3,332.875
3,332.875
-1
What non-zero, real value of $x$ satisfies $(5x)^4= (10x)^3$? Express your answer as a common fraction.
\frac{8}{5}
1
2,035.0625
2,035.0625
-1
Let $a,$ $b,$ $c$ be the roots of the cubic polynomial $x^3 - x - 1 = 0.$ Find \[a(b - c)^2 + b(c - a)^2 + c(a - b)^2.\]
-9
0.5625
5,506.125
4,570.444444
6,709.142857
Simplify $(1 + \tan 20^\circ)(1 + \tan 25^\circ).$
2
1
2,030.3125
2,030.3125
-1
A large rectangle is partitioned into four rectangles by two segments parallel to its sides. The areas of three of the resulting rectangles are shown. What is the area of the fourth rectangle?
15
Let's denote the large rectangle as $ABCD$, with $AB$ and $CD$ being the length and $BC$ and $AD$ being the width. Suppose two segments parallel to $AB$ and $BC$ partition $ABCD$ into four smaller rectangles: $PQRS$, $PQTU$, $UVWX$, and $RSWX$. Given the areas of three of these rectangles, we need to find the area of t...
0
5,932.0625
-1
5,932.0625
In triangle $ABC$, the sides opposite angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively, and $a=2b$. Also, $\sin A$, $\sin C$, $\sin B$ form an arithmetic sequence. $(I)$ Find the value of $\cos (B+C)$; $(II)$ If the area of $\triangle ABC$ is $\frac{8\sqrt{15}}{3}$, find the value of $c$.
4 \sqrt {2}
0
5,931.0625
-1
5,931.0625
$2(81+83+85+87+89+91+93+95+97+99)= $
1800
1. **Identify the sequence and its properties**: The sequence given in the problem is $81, 83, 85, 87, 89, 91, 93, 95, 97, 99$. This is an arithmetic sequence where each term increases by $2$. 2. **Sum the sequence**: The sum of an arithmetic sequence can be calculated using the formula for the sum of an arithmetic se...
0.9375
2,614.875
2,243.066667
8,192
Given that $α$ is an acute angle and $\sin α= \frac {3}{5}$, find the value of $\cos α$ and $\cos (α+ \frac {π}{6})$.
\frac {4\sqrt {3}-3}{10}
0
2,571.5
-1
2,571.5
A trauma hospital uses a rectangular piece of white cloth that is 60m long and 0.8m wide to make triangular bandages with both base and height of 0.4m. How many bandages can be made in total?
600
1
538.5625
538.5625
-1
Petya and Vasya are playing the following game. Petya chooses a non-negative random value $\xi$ with expectation $\mathbb{E} [\xi ] = 1$ , after which Vasya chooses his own value $\eta$ with expectation $\mathbb{E} [\eta ] = 1$ without reference to the value of $\xi$ . For which maximal value $p$ can Petya ch...
1/2
0
8,192
-1
8,192
Two trains are moving towards each other on parallel tracks - one with a speed of 60 km/h and the other with a speed of 80 km/h. A passenger sitting in the second train noticed that the first train passed by him in 6 seconds. What is the length of the first train?
233.33
0
4,102.1875
-1
4,102.1875
Let $f(x) = \left\lceil\dfrac{1}{x+2}\right\rceil$ for $x > -2$, and $f(x) = \left\lfloor\dfrac{1}{x+2}\right\rfloor$ for $x < -2$. ($f(x)$ is not defined at $x = -2$.) Which integer is not in the range of $f(x)$?
0
0.625
5,704.0625
4,211.3
8,192
Given that point $A(1,1)$ is a point on the ellipse $\frac{x^{2}}{a^{2}}+ \frac{y^{2}}{b^{2}}=1 (a > b > 0)$, and $F\_1$, $F\_2$ are the two foci of the ellipse such that $|AF\_1|+|AF\_2|=4$. (I) Find the standard equation of the ellipse; (II) Find the equation of the tangent line to the ellipse that passes through $A(...
\frac{1}{3}
0
8,192
-1
8,192
Given that $\sin \alpha $ and $\cos \alpha $ are the two roots of the quadratic equation $2x^{2}-x-m=0$ with respect to $x$, find $\sin \alpha +\cos \alpha =$______ and $m=\_\_\_\_\_\_$.
\frac{3}{4}
1
1,972.1875
1,972.1875
-1
Niffy's favorite number is a positive integer, and Stebbysaurus is trying to guess what it is. Niffy tells her that when expressed in decimal without any leading zeros, her favorite number satisfies the following: - Adding 1 to the number results in an integer divisible by 210 . - The sum of the digits of the number is...
1010309
Note that Niffy's favorite number must end in 9, since adding 1 makes it divisible by 10. Also, the sum of the digits of Niffy's favorite number must be even (because it is equal to twice the number of digits) and congruent to 2 modulo 3 (because adding 1 gives a multiple of 3 ). Furthermore, the sum of digits can be a...
0
8,192
-1
8,192
If $f(a)=a-2$ and $F(a,b)=b^2+a$, then $F(3,f(4))$ is:
7
1. **Calculate $f(4)$**: Given the function $f(a) = a - 2$, substitute $a = 4$: \[ f(4) = 4 - 2 = 2 \] 2. **Evaluate $F(3, f(4))$**: With $f(4) = 2$, we need to find $F(3, 2)$. The function $F(a, b) = b^2 + a$ is given, so substitute $a = 3$ and $b = 2$: \[ F(3, 2) = 2^2 + 3 = 4 + 3 = 7 \] 3. **Conc...
1
1,707.625
1,707.625
-1
An object moves $8$ cm in a straight line from $A$ to $B$, turns at an angle $\alpha$, measured in radians and chosen at random from the interval $(0,\pi)$, and moves $5$ cm in a straight line to $C$. What is the probability that $AC < 7$?
\frac{1}{3}
1. **Setup the coordinate system and define points**: - Let $B = (0, 0)$, $A = (0, -8)$. - The possible points of $C$ create a semi-circle of radius $5$ centered at $B$. 2. **Define the circles**: - The circle centered at $B$ with radius $5$ is described by the equation $x^2 + y^2 = 25$. - The circle cente...
0.8125
4,388.75
3,932.538462
6,365.666667
The sum of the digits of the integer equal to \( 777777777777777^2 - 222222222222223^2 \) can be found by evaluating the expression.
74
0.25
6,737.3125
5,398.75
7,183.5
What is $2^{-1} + 2^{-2} + 2^{-3} + 2^{-4} + 2^{-5} + 2^{-6} \pmod{13}$? Express your answer as an integer from $0$ to $12$, inclusive.
2
0.9375
4,561.4375
4,319.4
8,192
A rectangle has a perimeter of 80 inches and an area greater than 240 square inches. How many non-congruent rectangles meet these criteria?
13
0.625
5,478
5,895
4,783
$\triangle ABC$ has a right angle at $C$ and $\angle A = 20^\circ$. If $BD$ ($D$ in $\overline{AC}$) is the bisector of $\angle ABC$, then $\angle BDC =$
55^{\circ}
1. **Identify the angles in $\triangle ABC$:** - Since $\triangle ABC$ is a right triangle with $\angle C = 90^\circ$ and $\angle A = 20^\circ$, we can determine $\angle B$ using the fact that the sum of angles in a triangle is $180^\circ$: \[ \angle B = 180^\circ - \angle A - \angle C = 180^\circ - 20^\ci...
0.1875
8,011.0625
7,227
8,192
Given $f(x)=9^{x}-2×3^{x}+4$, where $x\in\[-1,2\]$: 1. Let $t=3^{x}$, with $x\in\[-1,2\}$, find the maximum and minimum values of $t$. 2. Find the maximum and minimum values of $f(x)$.
67
0.125
2,807.625
2,336.5
2,874.928571
Simplify first, then evaluate: $1-\frac{a-b}{a+2b}÷\frac{a^2-b^2}{a^2+4ab+4b^2}$. Given that $a=2\sin 60^{\circ}-3\tan 45^{\circ}$ and $b=3$.
-\sqrt{3}
0.875
2,902.8125
2,585.785714
5,122
Given real numbers $x$, $y$, $z$ satisfying $2x-y-2z-6=0$, and $x^2+y^2+z^2\leq4$, calculate the value of $2x+y+z$.
\frac{2}{3}
0.5
7,374.875
6,557.75
8,192
The probability that the random variable $X$ follows a normal distribution $N\left( 3,{{\sigma }^{2}} \right)$ and $P\left( X\leqslant 4 \right)=0.84$ can be expressed in terms of the standard normal distribution $Z$ as $P(Z\leqslant z)=0.84$, where $z$ is the z-score corresponding to the upper tail probability $1-0.84...
0.68
0.6875
5,973.4375
5,649.727273
6,685.6
In △ABC, B = $$\frac{\pi}{3}$$, AB = 8, BC = 5, find the area of the circumcircle of △ABC.
\frac{49\pi}{3}
0.25
3,475.9375
3,687
3,405.583333
Determine the heaviest weight that can be obtained using a combination of 2 lb and 4 lb, and 12 lb weights with a maximum of two weights used at a time.
16
0.3125
4,477.875
3,171.4
5,071.727273
A parallelogram-shaped paper WXYZ with an area of 7.17 square centimeters is placed on another parallelogram-shaped paper EFGH, as shown in the diagram. The intersection points A, C, B, and D are formed, and AB // EF and CD // WX. What is the area of the paper EFGH in square centimeters? Explain the reasoning.
7.17
0
6,429.125
-1
6,429.125
Let \(A B C D\) be a square of side length 13. Let \(E\) and \(F\) be points on rays \(A B\) and \(A D\), respectively, so that the area of square \(A B C D\) equals the area of triangle \(A E F\). If \(E F\) intersects \(B C\) at \(X\) and \(B X = 6\), determine \(D F\).
\sqrt{13}
0.75
6,144.0625
5,507.25
8,054.5
In $\triangle ABC$, the sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. Given that $a\sin 2B= \sqrt{3}b\sin A$. 1. Find $B$; 2. If $\cos A= \dfrac{1}{3}$, find the value of $\sin C$.
\dfrac{2\sqrt{6}+1}{6}
0
3,717.875
-1
3,717.875
If two distinct numbers are selected at random from the first seven prime numbers, what is the probability that their sum is an even number? Express your answer as a common fraction.
\frac{5}{7}
1
2,151.375
2,151.375
-1
If a number eight times as large as $x$ is increased by two, then one fourth of the result equals
2x + \frac{1}{2}
1. **Identify the expression**: The problem states that a number eight times as large as $x$ is increased by two. This can be expressed mathematically as: \[ 8x + 2 \] 2. **Calculate one fourth of the result**: We need to find one fourth of the expression obtained in step 1. This is done by multiplying the ex...
0.9375
3,072.5
2,781.266667
7,441
Given the quadratic function $f(x)=x^{2}+mx+n$. (1) If $f(x)$ is an even function with a minimum value of $1$, find the analytic expression of $f(x)$; (2) Under the condition of (1), for the function $g(x)= \frac {6x}{f(x)}$, solve the inequality $g(2^{x}) > 2^{x}$ with respect to $x$; (3) For the function $h(x)=|f(x)|...
\frac {1}{2}
0.5
7,390.625
6,773.5
8,007.75
Let $N$ be the number of ways of choosing a subset of $5$ distinct numbers from the set $$ {10a+b:1\leq a\leq 5, 1\leq b\leq 5} $$ where $a,b$ are integers, such that no two of the selected numbers have the same units digits and no two have the same tens digit. What is the remainder when $N$ is divided by $7...
47
1
3,081.125
3,081.125
-1
What is the sum of the eight terms in the arithmetic sequence $-2, 3, \dots, 33$?
124
0.9375
2,203.8125
1,804.6
8,192
A positive integer $a$ is input into a machine. If $a$ is odd, the output is $a+3$. If $a$ is even, the output is $a+5$. This process can be repeated using each successive output as the next input. If the input is $a=15$ and the machine is used 51 times, what is the final output?
218
If $a$ is odd, the output is $a+3$, which is even because it is the sum of two odd integers. If $a$ is even, the output is $a+5$, which is odd, because it is the sum of an even integer and an odd integer. Starting with $a=15$ and using the machine 2 times, we obtain $15 \rightarrow 15+3=18 \rightarrow 18+5=23$. Startin...
0.5
6,974.875
5,757.75
8,192
Given two spherical balls of different sizes placed in two corners of a rectangular room, where each ball touches two walls and the floor, and there is a point on each ball such that the distance from the two walls it touches to that point is 5 inches and the distance from the floor to that point is 10 inches, find the...
40
0.125
7,275.8125
3,667.5
7,791.285714
Consider the polynomials \[f(x)=1-12x+3x^2-4x^3+5x^4\] and \[g(x)=3-2x-6x^3+9x^4.\] Find $c$ such that the polynomial $f(x)+cg(x)$ has degree 3.
-\frac{5}{9}
1
2,155.375
2,155.375
-1
Given $ \frac {\pi}{2} < \alpha < \pi$ and $0 < \beta < \frac {\pi}{2}$, with $\tan \alpha= -\frac {3}{4}$ and $\cos (\beta-\alpha)= \frac {5}{13}$, find the value of $\sin \beta$.
\frac {63}{65}
0.8125
6,292.25
5,903.538462
7,976.666667
One night, 21 people exchanged phone calls $n$ times. It is known that among these people, there are $m$ people $a_{1}, a_{2}, \cdots, a_{m}$ such that $a_{i}$ called $a_{i+1}$ (for $i=1,2, \cdots, m$ and $a_{m+1}=a_{1}$), and $m$ is an odd number. If no three people among these 21 people have all exchanged calls with ...
101
0
7,818.5625
-1
7,818.5625
What is the nearest integer to $(3+\sqrt2)^6$?
7414
0
8,115.3125
-1
8,115.3125
There is a set of data: $a_{1}=\frac{3}{1×2×3}$, $a_{2}=\frac{5}{2×3×4}$, $a_{3}=\frac{7}{3×4×5}$, $\ldots $, $a_{n}=\frac{2n+1}{n(n+1)(n+2)}$. Let $S_{n}=a_{1}+a_{2}+a_{3}+\ldots +a_{n}$. Find the value of $S_{12}$. To solve this problem, Xiao Ming first simplified $a_{n}$ to $a_{n}=\frac{x}{(n+1)(n+2)}+\frac{y}{n(n+2...
\frac{201}{182}
0.5
7,534.25
7,459.125
7,609.375
A fair $6$-sided die is repeatedly rolled until an odd number appears. What is the probability that every even number appears at least once before the first occurrence of an odd number?
\frac{1}{20}
1. **Understanding the Problem**: We need to find the probability that all even numbers (2, 4, 6) appear at least once before the first odd number (1, 3, 5) appears when rolling a fair 6-sided die. 2. **Setting Up the Probability for Each Roll**: - The probability of rolling an odd number on any given roll is $\fra...
0
8,003.875
-1
8,003.875
An organization has a structure where there is one president, two vice-presidents (VP1 and VP2), and each vice-president supervises two managers. If the organization currently has 12 members, in how many different ways can the leadership (president, vice-presidents, and managers) be chosen?
554400
0
7,502.5625
-1
7,502.5625
The students' written work has a binary grading system, i.e., a work will either be accepted if it is done well or not accepted if done poorly. Initially, the works are checked by a neural network which makes an error in 10% of the cases. All works identified as not accepted by the neural network are then rechecked man...
66
0
6,085.25
-1
6,085.25
A bag contains 10 red marbles and 6 blue marbles. Three marbles are selected at random and without replacement. What is the probability that one marble is red and two are blue? Express your answer as a common fraction.
\frac{15}{56}
1
2,421.6875
2,421.6875
-1
Given the ellipse Q: $$\frac{x^{2}}{a^{2}} + y^{2} = 1 \quad (a > 1),$$ where $F_{1}$ and $F_{2}$ are its left and right foci, respectively. A circle with the line segment $F_{1}F_{2}$ as its diameter intersects the ellipse Q at exactly two points. (1) Find the equation of ellipse Q; (2) Suppose a line $l$ passing ...
\frac{3\sqrt{2}}{2}
0
8,136.375
-1
8,136.375
The base-10 numbers 217 and 45 are multiplied. The product is then written in base-6. What is the units digit of the base-6 representation?
3
0.875
2,794.9375
2,023.928571
8,192
Elena earns $\$ 13.25$ per hour working at a store. How much does Elena earn in 4 hours?
\$53.00
Elena works for 4 hours and earns $\$ 13.25$ per hour. This means that she earns a total of $4 \times \$ 13.25=\$ 53.00$.
0.6875
221.125
225.909091
210.6
For positive integers \( n \), let \( g(n) \) return the smallest positive integer \( k \) such that \( \frac{1}{k} \) has exactly \( n \) digits after the decimal point in base 6 notation. Determine the number of positive integer divisors of \( g(2023) \).
4096576
0
7,516.375
-1
7,516.375
Given the expansion of $(\sqrt{x} + \frac{2}{x^2})^n$, the ratio of the coefficient of the fifth term to the coefficient of the third term is 56:3. (Ⅰ) Find the constant term in the expansion; (Ⅱ) When $x=4$, find the term with the maximum binomial coefficient in the expansion.
\frac{63}{256}
0.375
7,279.625
6,493.5
7,751.3
A train departs from point $A$ and travels towards point $B$ at a uniform speed. 11 minutes later, another train departs from point $B$ traveling towards point $A$ at a constant speed on the same route. After their meeting point, it takes the trains 20 minutes and 45 minutes to reach $B$ and $A$, respectively. In what ...
9/5
0.1875
7,355.1875
5,658.333333
7,746.769231
In triangle $ABC$, $AB=13$, $BC=15$ and $CA=17$. Point $D$ is on $\overline{AB}$, $E$ is on $\overline{BC}$, and $F$ is on $\overline{CA}$. Let $AD=p\cdot AB$, $BE=q\cdot BC$, and $CF=r\cdot CA$, where $p$, $q$, and $r$ are positive and satisfy $p+q+r=2/3$ and $p^2+q^2+r^2=2/5$. The ratio of the area of triangle $DEF$ ...
61
0.1875
7,924
6,762.666667
8,192
Rationalize the denominator of $\displaystyle \frac{1}{\sqrt[3]{3} - \sqrt[3]{2}}$. With your answer in the form $\displaystyle \frac{\sqrt[3]{A} + \sqrt[3]{B} + \sqrt[3]{C}}{D}$, and the fraction in lowest terms, what is $A + B + C + D$?
20
1
2,710
2,710
-1
In triangle $ABC,$ $\cot A \cot C = \frac{1}{2}$ and $\cot B \cot C = \frac{1}{18}.$ Find $\tan C.$
4
0.6875
5,556.125
4,903.272727
6,992.4
An infinite sequence $ \,x_{0},x_{1},x_{2},\ldots \,$ of real numbers is said to be [b]bounded[/b] if there is a constant $ \,C\,$ such that $ \, \vert x_{i} \vert \leq C\,$ for every $ \,i\geq 0$. Given any real number $ \,a > 1,\,$ construct a bounded infinite sequence $ x_{0},x_{1},x_{2},\ldots \,$ such that \[ \ver...
1
To solve this problem, we need to construct a bounded sequence of real numbers \( x_0, x_1, x_2, \ldots \) such that for any two distinct nonnegative integers \( i \) and \( j \), the condition \[ |x_i - x_j| \cdot |i - j|^a \geq 1 \] is satisfied, given \( a > 1 \). ### Step-by-step Solution 1. **Defining the Seq...
0
8,192
-1
8,192
Points \( C_1 \), \( A_1 \), and \( B_1 \) are taken on the sides \( AB \), \( BC \), and \( AC \) of triangle \( ABC \) respectively, such that \[ \frac{AC_1}{C_1B} = \frac{BA_1}{A_1C} = \frac{CB_1}{B_1A} = 2. \] Find the area of triangle \( A_1B_1C_1 \) if the area of triangle \( ABC \) is 1.
\frac{1}{3}
0.125
7,958.1875
6,321.5
8,192
The sum of all numbers of the form $2k + 1$, where $k$ takes on integral values from $1$ to $n$ is:
$n(n+2)$
1. **Identify the sequence**: The problem asks for the sum of numbers of the form $2k + 1$ where $k$ ranges from $1$ to $n$. This forms a sequence of odd numbers starting from $3$ (when $k=1$, $2k+1=3$) up to $2n+1$ (when $k=n$, $2k+1=2n+1$). 2. **Write out the sequence explicitly**: The sequence is $3, 5, 7, \ldots, ...
0
2,979.0625
-1
2,979.0625
The number of terms in the expansion of $[(a+3b)^{2}(a-3b)^{2}]^{2}$ when simplified is:
5
1. **Simplify the given expression**: Start by applying the property of exponents to the expression $[(a+3b)^2(a-3b)^2]^2$: \[ [(a+3b)^2(a-3b)^2]^2 = [(a+3b)(a-3b)]^4 \] This simplification uses the property that $(x^m)^n = x^{mn}$ and the fact that $(a+3b)(a-3b)$ is a difference of squares. 2. **Apply...
1
3,465.4375
3,465.4375
-1
Three Graces each had the same number of fruits and met 9 Muses. Each Grace gave an equal number of fruits to each Muse. After that, each Muse and each Grace had the same number of fruits. How many fruits did each Grace have before meeting the Muses?
12
0.25
7,490.75
6,292.25
7,890.25
Among A, B, C, and D comparing their heights, the sum of the heights of two of them is equal to the sum of the heights of the other two. The average height of A and B is 4 cm more than the average height of A and C. D is 10 cm taller than A. The sum of the heights of B and C is 288 cm. What is the height of A in cm?
139
0.9375
3,187.125
2,853.466667
8,192
Given an ellipse $E$: $\frac{x^{2}}{a^{2}}+ \frac{y^{2}}{b^{2}}=1(a > b > 0)$ with an eccentricity of $\frac{\sqrt{3}}{2}$ and a minor axis length of $2$. 1. Find the equation of the ellipse $E$; 2. A line $l$ is tangent to a circle $C$: $x^{2}+y^{2}=r^{2}(0 < r < b)$ at any point and intersects the ellipse $E$ at poin...
\frac{2\sqrt{5}}{5}
0
6,337.75
-1
6,337.75
Each of \( A \), \( B \), \( C \), and \( D \) is a positive two-digit integer. These integers satisfy each of the equations \[ \begin{aligned} B &= 3C \\ D &= 2B - C \\ A &= B + D \end{aligned} \] What is the largest possible value of \( A + B + C + D \)?
204
1
3,660.125
3,660.125
-1
What is the remainder when $2^{202} + 202$ is divided by $2^{101} + 2^{51} + 1$?
201
1. **Substitute and Simplify**: Let $x = 2^{50}$. We need to find the remainder when $2^{202} + 202$ is divided by $2^{101} + 2^{51} + 1$. Rewriting the terms using $x$, we have: \[ 2^{202} = (2^{101})^2 = (2^{50} \cdot 2^{51})^2 = (x \cdot 2x)^2 = 4x^4 \] and \[ 2^{101} + 2^{51} + 1 = x^2 \cdot 2 + x...
0.5625
5,582.875
3,553.555556
8,192
A right rectangular prism $Q$ has integral side lengths $a, b, c$ with $a \le b \le c$. A plane parallel to one of the faces of $Q$ cuts $Q$ into two prisms, one of which is similar to $Q$, with both having nonzero volumes. The middle side length $b = 3969$. Determine the number of ordered triples $(a, b, c)$ that allo...
12
0
8,192
-1
8,192
Determine the least possible value of $f(1998),$ where $f:\Bbb{N}\to \Bbb{N}$ is a function such that for all $m,n\in {\Bbb N}$, \[f\left( n^{2}f(m)\right) =m\left( f(n)\right) ^{2}. \]
120
To find the least possible value of \( f(1998) \), where \( f: \mathbb{N} \to \mathbb{N} \) satisfies the functional equation \[ f\left( n^{2}f(m)\right) = m\left( f(n)\right) ^{2} \] for all \( m, n \in \mathbb{N} \), we begin by analyzing the given equation. Firstly, let's examine the case when \( m = 1 \): \[ ...
0
7,731.25
-1
7,731.25
Let $f(t)=\frac{t}{1-t}$, $t \not= 1$. If $y=f(x)$, then $x$ can be expressed as
-f(-y)
1. Given the function $f(t) = \frac{t}{1-t}$, we know that $y = f(x)$, which implies: \[ y = \frac{x}{1-x} \] 2. We rearrange the equation to solve for $x$ in terms of $y$: \[ y(1-x) = x \implies y - yx = x \implies y = x + yx \implies y = x(1+y) \] \[ x = \frac{y}{1+y} \] 3. We need to fin...
0
2,249
-1
2,249
Define: \( a \oplus b = a \times b \), \( c \bigcirc d = d \times d \times d \times \cdots \times d \) (d multiplied c times). Find \( (5 \oplus 8) \oplus (3 \bigcirc 7) \).
13720
0.3125
1,117.5625
1,630.2
884.545455
The pentagon \(PQRST\) is divided into four triangles with equal perimeters. The triangle \(PQR\) is equilateral. \(PTU\), \(SUT\), and \(RSU\) are congruent isosceles triangles. What is the ratio of the perimeter of the pentagon \(PQRST\) to the perimeter of the triangle \(PQR\)?
5:3
0
8,184.4375
-1
8,184.4375
One interior angle of a convex polygon is 160 degrees. The rest of the interior angles of the polygon are each 112 degrees. How many sides does the polygon have?
6
1
1,933.875
1,933.875
-1