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Allyn is a golfer. At the starting tee, he hit the golf ball and it traveled 180 yards straight toward the hole. On his second turn, he hit the ball again straight toward the hole and it traveled half as far as it did on his first turn, but the ball landed 20 yards beyond the hole. On his third swing, he hit the ball...
On his second turn, the ball traveled 180/2=<<180/2=90>>90 yards. After two turns, the ball had traveled 180+90=<<180+90=270>>270 yards. Since, after the second turn, the ball was 20 yards past the hole, this means the distance from the starting tee to the hole was 270-20=<<270-20=250>>250 yards. #### 250
The probability that students A and B stand together among three students A, B, and C lined up in a row is what?
\frac{2}{3}
If non-zero vectors $\overrightarrow{a}$ and $\overrightarrow{b}$ satisfy $|\overrightarrow{a}| = |\overrightarrow{b}|$ and $(\sqrt{3}\overrightarrow{a} - 2\overrightarrow{b}) \cdot \overrightarrow{a} = 0$, then the angle between $\overrightarrow{a}$ and $\overrightarrow{b}$ is __________.
\frac{\pi}{6}
Five positive consecutive integers starting with $a$ have average $b$. What is the average of 5 consecutive integers that start with $b$?
$a+4$
Vasya thought of a four-digit number and wrote down the product of each pair of its adjacent digits on the board. After that, he erased one product, and the numbers 20 and 21 remained on the board. What is the smallest number Vasya could have in mind?
3745
Lexie and Tom went apple picking. Lexie picked 12 apples and Tom picked twice as many apples. How many apples did they collect altogether?
Tom picked 12 x 2 = <<12*2=24>>24 apples Altogether, they picked 12 + 24 = <<12+24=36>>36 apples #### 36
For non-negative integers \( x \), the function \( f(x) \) is defined as follows: $$ f(0) = 0, \quad f(x) = f\left(\left\lfloor \frac{x}{10} \right\rfloor\right) + \left\lfloor \log_{10} \left( \frac{10}{x - 10\left\lfloor \frac{x-1}{10} \right\rfloor} \right) \right\rfloor . $$ For \( 0 \leqslant x \leqslant 2006 \), ...
1111
Jaylen has 5 carrots and 2 cucumbers. Jaylen has twice as many bell peppers as Kristin. Jaylen has 3 less than half as many green beans as Kristin. If Kristin has 2 bell peppers and 20 green beans, how many vegetables does Jaylen have in total?
Jaylen has 2 * 2 = <<2*2=4>>4 bell peppers Jaylen has (20 / 2) - 3 = <<20/2-3=7>>7 green beans Jaylen has a total of 4 + 7 + 5 + 2 = <<4+7+5+2=18>>18 vegetables #### 18
Two cards are chosen at random from a standard 52-card deck. What is the probability that both cards are numbers (2 through 10) and total to 15?
\frac{8}{221}
What is the greatest 3-digit base 8 positive integer that is divisible by 5? (Express your answer in base 8.)
776_8
Hugh had eight pounds of candy, Tommy had six pounds of candy, and Melany had seven pounds of candy. If they share the candy equally, how much will each person have?
Hugh and Tommy have a total of 8+6 = <<8+6=14>>14 candies. Since Melany also has seven candies, they have 14+7 = <<14+7=21>>21 candies. If they combine and share the candies equally, each person will get 21/3 = <<21/3=7>>7 candies. #### 7
For how many (not necessarily positive) integer values of $n$ is the value of $4000 \cdot \left(\frac{2}{5}\right)^n$ an integer?
9
Find the number of triples of natural numbers \( m, n, k \) that are solutions to the equation \( m + \sqrt{n+\sqrt{k}} = 2023 \).
27575680773
As $x$ ranges over all real numbers, find the range of \[f(x) = \sin^4 x + \cos ^2 x.\]Enter your answer using interval notation.
\left[ \frac{3}{4}, 1 \right]
The number $r$ can be expressed as a four-place decimal $0.abcd,$ where $a, b, c,$ and $d$ represent digits, any of which could be zero. It is desired to approximate $r$ by a fraction whose numerator is 1 or 2 and whose denominator is an integer. The closest such fraction to $r$ is $\frac 27.$ What is the number of pos...
417
Find the modular inverse of $4$, modulo $21$. Express your answer as an integer from $0$ to $20$, inclusive.
16
Ryan is looking for people to crowdfund his new business idea. If the average person funds $10 to a project they're interested in, how many people will Ryan have to recruit to fund a $1,000 business if he has $200 already?
First, we need to determine how much money Ryan needs to hit his goal which we find by subtracting his available cash from his target, performing 1000-200=<<1000-200=800>>800 dollars needed. Since the average person contributes $10 when crowdfunding, this means he needs to find 800/10=<<800/10=80>>80 people to fund his...
Let $ABCD$ be a trapezium with $AB// DC, AB = b, AD = a ,a<b$ and $O$ the intersection point of the diagonals. Let $S$ be the area of the trapezium $ABCD$ . Suppose the area of $\vartriangle DOC$ is $2S/9$ . Find the value of $a/b$ .
\frac{2 + 3\sqrt{2}}{7}
John's car needs a new engine. The labor costs $75 an hour for 16 hours. The part itself cost $1200. How much did the repairs cost in total?
The labor cost 16*$75=$<<16*75=1200>>1200 So the total cost was $1200+$1200=$<<1200+1200=2400>>2400 #### 2400
Hillary's teacher assigned 1 hour of reading during the weekend. On Friday night, Hillary read for 16 minutes. On Saturday she read for 28 minutes. How many minutes does Hillary have to read on Sunday to complete the assignment?
Hillary needs to read for 1 hour which equals 60 minutes. Hillary has read for a total of 16 minutes + 28 = <<16+28=44>>44 minutes so far. Hillary will need to read for 60 minutes - 44 = <<60-44=16>>16 minutes on Sunday. #### 16
What is the largest possible remainder that is obtained when a two-digit number is divided by the sum of its digits?
15
There are three pairs of real numbers $(x_1,y_1)$, $(x_2,y_2)$, and $(x_3,y_3)$ that satisfy both $x^3 - 3xy^2 = 2017$ and $y^3 - 3x^2y = 2016$. Compute $\left(2 - \frac{x_1}{y_1}\right)\left(2 - \frac{x_2}{y_2}\right)\left(2 - \frac{x_3}{y_3}\right)$.
\frac{26219}{2016}
In the polar coordinate system and the Cartesian coordinate system xOy, which have the same unit of length, with the origin O as the pole and the positive half-axis of x as the polar axis. The parametric equation of line l is $$\begin{cases} x=2+ \frac {1}{2}t \\ y= \frac { \sqrt {3}}{2}t \end{cases}$$ (t is the parame...
\frac {8 \sqrt {7}}{3}
What is the smallest number, \( n \), which is the product of 3 distinct primes where the mean of all its factors is not an integer?
130
Let \[f(n) = \begin{cases} n^2-1 & \text{ if }n < 4, \\ 3n-2 & \text{ if }n \geq 4. \end{cases} \]Find $f(f(f(2)))$.
22
Segment $AB$ has midpoint $C$, and segment $BC$ has midpoint $D$. Semi-circles are constructed with diameters $\overline{AB}$ and $\overline{BC}$ to form the entire region shown. Segment $CP$ splits the region into two sections of equal area. What is the degree measure of angle $ACP$? Express your answer as a decimal t...
112.5
If $x^2+y^2=1$, what is the largest possible value of $|x|+|y|$?
\sqrt{2}
A teacher drew a rectangle $ABCD$ on the board. A student named Petya divided this rectangle into two rectangles with a line parallel to side $AB$. It turned out that the areas of these parts are in the ratio 1:2, and their perimeters are in the ratio 3:5 (in the same order). Another student named Vasya divided this re...
20/19
Compute the number of ordered pairs of integers $(x,y)$ with $1\le x<y\le 100$ such that $i^x+i^y$ is a real number.
1850
Let \[f(x)=\cos(x^3-4x^2+5x-2).\] If we let $f^{(k)}$ denote the $k$ th derivative of $f$ , compute $f^{(10)}(1)$ . For the sake of this problem, note that $10!=3628800$ .
907200
Distribute 6 volunteers into 4 groups, with each group having at least 1 and at most 2 people, and assign them to four different exhibition areas of the fifth Asia-Europe Expo. The number of different allocation schemes is ______ (answer with a number).
1080
A fair 6-sided die is rolled. If I roll $n$, then I win $n^2$ dollars. What is the expected value of my win? Express your answer as a dollar value rounded to the nearest cent.
\$15.17
What is the sum of all possible values of $t$ between $0$ and $360$ such that the triangle in the coordinate plane whose vertices are $(\cos 40^\circ,\sin 40^\circ)$, $(\cos 60^\circ,\sin 60^\circ)$, and $(\cos t^\circ,\sin t^\circ)$ is isosceles?
380
Mary and James each sit in a row of 7 chairs. They choose their seats at random. What is the probability that they don't sit next to each other?
\frac{5}{7}
If the polynomial $x^3+x^{10}=a_0+a_1(x+1)+\ldots+a_9(x+1)^9+a_{10}(x+1)^{10}$, then $a_2=$ ______.
42
Let $n$ be a positive integer. For $i$ and $j$ in $\{1,2,\dots,n\}$, let $s(i,j)$ be the number of pairs $(a,b)$ of nonnegative integers satisfying $ai +bj=n$. Let $S$ be the $n$-by-$n$ matrix whose $(i,j)$ entry is $s(i,j)$. For example, when $n=5$, we have $S = \begin{bmatrix} 6 & 3 & 2 & 2 & 2 \\ 3 & 0 & 1 & 0 & 1 \...
(-1)^{\lceil n/2 \rceil-1} 2 \lceil \frac{n}{2} \rceil
Point \( M \) lies on the edge \( AB \) of cube \( ABCD A_1 B_1 C_1 D_1 \). Rectangle \( MNLK \) is inscribed in square \( ABCD \) in such a way that one of its vertices is at point \( M \), and the other three vertices are located on different sides of the base square. Rectangle \( M_1N_1L_1K_1 \) is the orthogonal pr...
1:4
(15) Given the following propositions: (1) "If $x > 2$, then $x > 0$" - the negation of the proposition (2) "For all $a \in (0, +\infty)$, the function $y = a^x$ is strictly increasing on its domain" - the negation (3) "$π$ is a period of the function $y = \sin x$" or "$2π$ is a period of the function $y = \sin 2x$"...
(2)(3)
In the diagram below, $ABCD$ is a rectangle with side lengths $AB=3$ and $BC=11$, and $AECF$ is a rectangle with side lengths $AF=7$ and $FC=9,$ as shown. The area of the shaded region common to the interiors of both rectangles is $\frac mn$, where $m$ and $n$ are relatively prime positive integers. Find $m+n$.
65
If $f(a)=a-2$ and $F(a,b)=b^2+a$, then $F(3,f(4))$ is:
7
For some constants \( c \) and \( d \), let \[ g(x) = \left\{ \begin{array}{cl} cx + d & \text{if } x < 3, \\ 10 - 2x & \text{if } x \ge 3. \end{array} \right.\] The function \( g \) has the property that \( g(g(x)) = x \) for all \( x \). What is \( c + d \)?
4.5
Cat and Claire are having a conversation about Cat's favorite number. Cat says, "My favorite number is a two-digit positive integer with distinct nonzero digits, $\overline{AB}$ , such that $A$ and $B$ are both factors of $\overline{AB}$ ." Claire says, "I don't know your favorite number yet, but I do k...
24
Given $\sin 2α - 2 = 2\cos 2α$, find the value of $\sin^{2}α + \sin 2α$.
\frac{8}{5}
How many elements are in the set obtained by transforming $\{(0,0),(2,0)\} 14$ times?
477
A right triangle has perimeter $32$ and area $20$. What is the length of its hypotenuse?
\frac{59}{4}
What is the smallest positive integer that is both a multiple of $7$ and a multiple of $4$?
28
Given $α∈(\frac{\pi}{2},π)$, $\sin α =\frac{\sqrt{5}}{5}$. (Ⅰ) Find the value of $\tan\left( \frac{\pi}{4}+2α \right)$; (Ⅱ) Find the value of $\cos\left( \frac{5\pi}{6}-2α \right)$.
-\frac{3\sqrt{3}+4}{10}
A hotel has 10 rooms and is currently full. Each room holds a family of 3. If each person receives 2 towels, how many towels does the hotel hand out?
The rooms are full so there are currently 10 rooms * 3 people = <<10*3=30>>30 people in the hotel. So the hotel hands out 30 people * 2 towels = <<30*2=60>>60 towels. #### 60
A tree grows in a rather peculiar manner. Lateral cross-sections of the trunk, leaves, branches, twigs, and so forth are circles. The trunk is 1 meter in diameter to a height of 1 meter, at which point it splits into two sections, each with diameter .5 meter. These sections are each one meter long, at which point they ...
\pi / 2
Let $\mathcal{S}$ be the set $\{1, 2, 3, \dots, 12\}$. Let $n$ be the number of sets of two non-empty disjoint subsets of $\mathcal{S}$. Calculate the remainder when $n$ is divided by 500.
125
Given that the function $f(x)$ satisfies: $4f(x)f(y)=f(x+y)+f(x-y)$ $(x,y∈R)$ and $f(1)= \frac{1}{4}$, find $f(2014)$.
- \frac{1}{4}
What is the value of $x$ in the equation $\sqrt{\frac{72}{25}} = \sqrt[4]{\frac{x}{25}}$?
207.36
If the function $f(x)=\frac{1}{2}(2-m)x^{2}+(n-8)x+1$ $(m > 2)$ is monotonically decreasing in the interval $[-2,-1]$, find the maximum value of $mn$.
18
In the expansion of $(x^2+ \frac{4}{x^2}-4)^3(x+3)$, find the constant term.
-240
A square is inscribed in an equilateral triangle such that each vertex of the square touches the perimeter of the triangle. One side of the square intersects and forms a smaller equilateral triangle within which we inscribe another square in the same manner, and this process continues infinitely. What fraction of the e...
\frac{3 - \sqrt{3}}{2}
Given the function $f(x)=4\cos ωx\sin \left(wx- \frac{π}{6}\right)$ $(ω > 0)$ with the smallest positive period of $π$. (1) Find $ω$; (2) In triangle $△ABC$, the sides opposite to angles $A$, $B$, $C$ are $a$, $b$, $c$ respectively. It is known that the acute angle $A$ is a zero point of the function $f(x)$, and $\si...
2\sqrt{2}
Given that Ben spent some amount of money and David spent $0.5 less for each dollar Ben spent, and Ben paid $16.00 more than David, determine the total amount they spent together in the bagel store.
48.00
Mark has a cursed six-sided die that never rolls the same number twice in a row, and all other outcomes are equally likely. Compute the expected number of rolls it takes for Mark to roll every number at least once.
\frac{149}{12}
Find all prime numbers $ p,q,r$, such that $ \frac{p}{q}\minus{}\frac{4}{r\plus{}1}\equal{}1$
(7, 3, 2), (5, 3, 5), (3, 2, 7)
Jacob uses the following procedure to write down a sequence of numbers. First he chooses the first term to be 6. To generate each succeeding term, he flips a fair coin. If it comes up heads, he doubles the previous term and subtracts 1. If it comes up tails, he takes half of the previous term and subtracts 1. What is t...
\frac{5}{8}
Calculate: \(\left[\left(11 \frac{1}{9}-3 \frac{2}{5} \times 1 \frac{2}{17}\right)-8 \frac{2}{5} \div 3.6\right] \div 2 \frac{6}{25}\).
\frac{20}{9}
Each segment with endpoints at the vertices of a regular 100-gon is painted red if there is an even number of vertices between its endpoints, and blue otherwise (in particular, all sides of the 100-gon are red). Numbers are placed at the vertices such that the sum of their squares equals 1, and the products of the numb...
1/2
Calculate the value of the expression $$ \frac{\left(3^{4}+4\right) \cdot\left(7^{4}+4\right) \cdot\left(11^{4}+4\right) \cdot \ldots \cdot\left(2015^{4}+4\right) \cdot\left(2019^{4}+4\right)}{\left(1^{4}+4\right) \cdot\left(5^{4}+4\right) \cdot\left(9^{4}+4\right) \cdot \ldots \cdot\left(2013^{4}+4\right) \cdot\left(...
4080401
Two stores have warehouses storing millet: the first warehouse has 16 tons more than the second. Every night, exactly at midnight, the owner of each store steals a quarter of their competitor's millet and moves it to their own warehouse. After 10 nights, the thieves were caught. Which warehouse had more millet at the m...
2^{-6}
Consider the set of all triangles $OPQ$ where $O$ is the origin and $P$ and $Q$ are distinct points in the plane with nonnegative integer coordinates $(x,y)$ such that $29x + y = 2035$. Find the number of such distinct triangles whose area is a positive integer.
1225
Suppose $x$ is in the interval $[0, \pi/2]$ and $\log_{24\sin x} (24\cos x)=\frac{3}{2}$. Find $24\cot^2 x$.
192
What is the product of the solutions of the equation $-35=-x^2-2x?$
-35
A point $(x,y)$ is randomly and uniformly chosen inside the rectangle with vertices (0,0), (0,3), (4,3), and (4,0). What is the probability that $x + 2y < 6$?
\dfrac{2}{3}
Six chairs sit in a row. Six people randomly seat themselves in the chairs. Each person randomly chooses either to set their feet on the floor, to cross their legs to the right, or to cross their legs to the left. There is only a problem if two people sitting next to each other have the person on the right crossing t...
1106
Two painters are painting a fence that surrounds garden plots. They come every other day and paint one plot (there are 100 plots) in either red or green. The first painter is colorblind and mixes up the colors; he remembers which plots he painted, but cannot distinguish the color painted by the second painter. The firs...
49
The number of different arrangements of $6$ rescue teams to $3$ disaster sites, where site $A$ has at least $2$ teams and each site is assigned at least $1$ team.
360
A train has 18 identical cars. In some of the cars, half of the seats are free, in others, one third of the seats are free, and in the remaining cars, all the seats are occupied. In the entire train, exactly one ninth of all seats are free. How many cars have all seats occupied?
13
In triangle $ABC$, the sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. Given that $a^2 + c^2 - b^2 = ac$, $c=2$, and point $G$ satisfies $|\overrightarrow{BG}| = \frac{\sqrt{19}}{3}$ and $\overrightarrow{BG} = \frac{1}{3}(\overrightarrow{BA} + \overrightarrow{BC})$, find $\sin A$.
\frac{3 \sqrt{21}}{14}
Find $a+b+c$ if the graph of the equation $y=ax^2+bx+c$ is a parabola with vertex $(5,3)$, vertical axis of symmetry, and contains the point $(2,0)$.
-\frac73
How many distinct prime factors does the sum of the positive divisors of $400$ have?
1
The two digits in Jack's age are the same as the digits in Bill's age, but in reverse order. In five years Jack will be twice as old as Bill will be then. What is the difference in their current ages?
18
Thirty people are divided into three groups (I, II, and III) with 10 people in each group. How many different compositions of groups can there be?
\frac{30!}{(10!)^3}
When five students are lining up to take a photo, and two teachers join in, with the order of the five students being fixed, calculate the total number of ways for the two teachers to stand in line with the students for the photo.
42
What is the number of units in the area of the circle with center at $P$ and passing through $Q$? Express your answer in terms of $\pi$. [asy] size(150); pair P = (-3,4), Q=(9,-3); string stringpair(pair p){return "$("+string(p.x)+", "+string(p.y)+"$)";} draw((-15,0)--(15,0),Arrows(4)); draw((0,-15)--(0,15),Arrows(4))...
193\pi
How many positive divisors does $24$ have?
8
Forty teams play a tournament in which every team plays every other team exactly once. No ties occur, and each team has a $50 \%$ chance of winning any game it plays. The probability that no two teams win the same number of games is $\frac mn,$ where $m$ and $n$ are relatively prime positive integers. Find $\log_2 n.$
742
Suppose \(2+\frac{1}{1+\frac{1}{2+\frac{2}{3+x}}}=\frac{144}{53}.\)What is the value of \(x?\)
\frac{3}{4}
Last night, Olive charged her phone for 10 hours. Assuming each hour of charge lasts the phone 2 hours of use, calculate the total time Olive would be able to use her phone before it goes off if she charges it for 3/5 of the time she charged the phone last night.
If Olive charges her phone for 3/5 of the time she charged the phone last night, the phone would be charged for 3/5*10=<<3/5*10=6>>6 hours. Assuming each hour of charge lasts the phone 2 hours of use, the phone will last for 6*2=<<6*2=12>>12 hours before it goes off when Olive uses it on a six hours charge. #### 12
Given the set \( A=\left\{\left.\frac{a_{1}}{9}+\frac{a_{2}}{9^{2}}+\frac{a_{3}}{9^{3}}+\frac{a_{4}}{9^{4}} \right\rvert\, a_{i} \in\{0,1,2, \cdots, 8\}, i=1, 2, 3, 4\} \), arrange the numbers in \( A \) in descending order and find the 1997th number.
\frac{6}{9} + \frac{2}{81} + \frac{3}{729} + \frac{1}{6561}
Let $\omega$ be a nonreal root of $z^3 = 1.$ Find the number of ordered pairs $(a,b)$ of integers such that $|a \omega + b| = 1.$
6
A rectangular picture frame is constructed from 1.5-inch-wide pieces of wood. The area of just the frame is \(27\) square inches, and the length of one of the interior edges of the frame is \(4.5\) inches. Determine the sum of the lengths of the four interior edges of the frame.
12
Maisie and Donna dropped off flyers for a neighborhood clean-up day at houses around their neighborhood. Maisie walked down the shorter left street and dropped off 33 flyers. Donna took the long right street on her bicycle and dropped off five more than twice as many flyers as Maisie. How many flyers did Donna drop off...
Twice as many flyers as Maisie is 33 * 2 = <<33*2=66>>66 flyers. Donna dropped off five more than that, so she dropped off 66 + 5 = <<66+5=71>>71 flyers. #### 71
What is the smallest prime whose digits sum to \(28\)?
1999
At Ken's local store, a pound of steak is going for $7. He decides to get two pounds. At the till, he pays using a $20 bill. How much money will he get back?
2 pounds of steak will cost Ken 2 * 7 = <<2*7=14>>14 dollars Subtracting that amount from $20 will give 20 - 14 = <<20-14=6>>6 dollars Ken will therefore get 6 dollars back. #### 6
$\left(\frac{1}{4}\right)^{-\frac{1}{4}}=$
\sqrt{2}
Let \( n \) be a two-digit number such that the square of the sum of the digits of \( n \) is equal to the sum of the digits of \( n^2 \). Find the sum of all possible values of \( n \).
139
Xiao Ming set a six-digit passcode for his phone using the numbers $0-9$, but he forgot the last digit. The probability that Xiao Ming can unlock his phone with just one try is ____.
\frac{1}{10}
How many functions $f:\{1,2, \ldots, 10\} \rightarrow\{1,2, \ldots, 10\}$ satisfy the property that $f(i)+f(j)=11$ for all values of $i$ and $j$ such that $i+j=11$.
100000
Pat's stick is 30 inches long. He covers 7 inches of the stick in dirt. The portion that is not covered in dirt is half as long as Sarah’s stick. Jane’s stick is two feet shorter than Sarah’s stick. How many inches long is Jane’s stick?
30-7 = <<30-7=23>>23 inches of Pat’s stick is not covered in dirt. Sarah’s stick is 23*2 = <<23*2=46>>46 inches long. Jane’s stick is 12*2 = <<12*2=24>>24 inches shorter than Sarah’s stick. Jane’s stick is 46-24 = <<46-24=22>>22 inches long. #### 22
Given that player A needs to win 2 more games and player B needs to win 3 more games, and the probability of winning each game for both players is $\dfrac{1}{2}$, calculate the probability of player A ultimately winning.
\dfrac{11}{16}
Starting with the number 100, Shaffiq repeatedly divides his number by two and then takes the greatest integer less than or equal to that number. How many times must he do this before he reaches the number 1?
6
The region consisting of all points in three-dimensional space within 3 units of line segment $\overline{AB}$ has volume $216\pi$. What is the length $\textit{AB}$?
20
Find the value of $x,$ if \[|x-20| + |x-18| = |2x-36|.\]
19
What is the minimum number of squares that need to be colored in a 65x65 grid (totaling 4,225 squares) so that among any four cells forming an "L" shape, there is at least one colored square?
1408
Let $(b_1,b_2,b_3,\ldots,b_{10})$ be a permutation of $(1,2,3,\ldots,10)$ for which $b_1>b_2>b_3>b_4 \mathrm{\ and \ } b_4<b_5<b_6<b_7<b_8<b_9<b_{10}.$ Find the number of such permutations.
84