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How many sequences of $0$s and $1$s of length $20$ are there that begin with a $0$, end with a $0$, contain no two consecutive $0$s, and contain no four consecutive $1$s? A) 65 B) 75 C) 85 D) 86 E) 95
86
Using each of the digits 1-9 exactly once, form a two-digit perfect square, a three-digit perfect square, and a four-digit perfect square. What is the smallest four-digit perfect square among them?
1369
If $F(n+1)=\frac{2F(n)+1}{2}$ for $n=1,2,\cdots$ and $F(1)=2$, then $F(101)$ equals:
52
A magazine printed photos of three celebrities along with three photos of the celebrities as babies. The baby pictures did not identify the celebrities. Readers were asked to match each celebrity with the correct baby pictures. What is the probability that a reader guessing at random will match all three correctly?
\frac{1}{6}
What is the maximum number of kings, not attacking each other, that can be placed on a standard $8 \times 8$ chessboard?
16
If the operation $Z$ is defined as $a Z b = b + 10a - a^2$, what is the value of $2Z6$?
22
Equilateral triangle $ABC$ and square $BCDE$ are coplanar, as shown. What is the number of degrees in the measure of angle $CAD$? [asy] size(70); draw((0,0)--(20,0)--(20,20)--(0,20)--cycle); draw((0,20)--(10,37.3)--(20,20)); draw((10,37.3)--(20,0)); label("$A$",(10,37.3),N); label("$B$",(0,20),W); label("$C$",(20,20),...
15
Select the shape of diagram $b$ from the regular hexagonal grid of diagram $a$. There are $\qquad$ different ways to make the selection (note: diagram $b$ can be rotated).
72
The area of rectangle PRTV is divided into four rectangles, PQXW, QRSX, XSTU, and WXUV. Given that the area of PQXW is 9, the area of QRSX is 10, and the area of XSTU is 15, find the area of rectangle WXUV.
\frac{27}{2}
An urn contains one red ball and one blue ball. A box of extra red and blue balls lies nearby. George performs the following operation four times: he draws a ball from the urn at random and then takes a ball of the same color from the box and returns those two matching balls to the urn. After the four iterations the ur...
\frac{1}{5}
If $\sqrt[3]{0.3}\approx 0.6694$ and $\sqrt[3]{3}\approx 1.442$, then $\sqrt[3]{300}\approx$____.
6.694
Given a cone-shaped island with a total height of 12000 feet, where the top $\frac{1}{4}$ of its volume protrudes above the water level, determine how deep the ocean is at the base of the island.
1092
Which of the following is equal to $110 \%$ of 500?
550
Given a quadratic function $y=-x^{2}+bx+c$ where $b$ and $c$ are constants. $(1)$ If $y=0$ and the corresponding values of $x$ are $-1$ and $3$, find the maximum value of the quadratic function. $(2)$ If $c=-5$, and the quadratic function $y=-x^{2}+bx+c$ intersects the line $y=1$ at a unique point, find the express...
-4
Jamie has a jar of coins containing the same number of nickels, dimes and quarters. The total value of the coins in the jar is $\$$13.20. How many nickels does Jamie have?
33
Two adjacent faces of a tetrahedron are equilateral triangles with a side length of 1 and form a dihedral angle of 45 degrees. The tetrahedron rotates around the common edge of these faces. Find the maximum area of the projection of the rotating tetrahedron onto a plane that contains the given edge.
\frac{\sqrt{3}}{4}
What is the 39th number in the row of Pascal's triangle that has 41 numbers?
780
Angela has deposited $\$8,\!000$ into an account that pays $6\%$ interest compounded annually. Bob has deposited $\$10,\!000$ into an account that pays $7\%$ simple annual interest. In $20$ years Angela and Bob compare their respective balances. To the nearest dollar, what is the positive difference between their bal...
\$1,\!657
If the $whatsis$ is $so$ when the $whosis$ is $is$ and the $so$ and $so$ is $is \cdot so$, what is the $whosis \cdot whatsis$ when the $whosis$ is $so$, the $so$ and $so$ is $so \cdot so$ and the $is$ is two ($whatsis, whosis, is$ and $so$ are variables taking positive values)?
$so \text{ and } so$
Suppose that \(a, b, c,\) and \(d\) are positive integers which are not necessarily distinct. If \(a^{2}+b^{2}+c^{2}+d^{2}=70\), what is the largest possible value of \(a+b+c+d?\)
16
On a particular day, Rose's teacher read the register and realized there were twice as many girls as boys present on that day. The class has 250 students, and all the 140 girls were present. If all the absent students were boys, how many boys were absent that day?
If there were twice as many girls as boys present that day, then the number of boys is 140 girls / 2 girls/boy = <<140/2=70>>70 boys. The total number of students present that day is 140 girls + 70 boys = <<140+70=210>>210 students. If the class has 250 students, then the number of boys absent is 250 students - 210 stu...
A cinema has 21 rows of seats, with 26 seats in each row. How many seats are there in total in this cinema?
546
Compute the number of ordered pairs of integers $(a, b)$, with $2 \leq a, b \leq 2021$, that satisfy the equation $$a^{\log _{b}\left(a^{-4}\right)}=b^{\log _{a}\left(b a^{-3}\right)}.$$
43
Find $AB + AC$ in triangle $ABC$ given that $D$ is the midpoint of $BC$, $E$ is the midpoint of $DC$, and $BD = DE = EA = AD$.
1+\frac{\sqrt{3}}{3}
Complex numbers $p,$ $q,$ and $r$ are zeros of a polynomial $Q(z) = z^3 + sz^2 + tz + u,$ and $|p|^2 + |q|^2 + |r|^2 = 360.$ The points corresponding to $p,$ $q,$ and $r$ in the complex plane are the vertices of a right triangle with hypotenuse $k.$ Find $k^2.$
540
When the vectors $\begin{pmatrix} 4 \\ 1 \end{pmatrix}$ and $\begin{pmatrix} -1 \\ 3 \end{pmatrix}$ are both projected onto the same vector $\mathbf{v},$ the result is $\mathbf{p}$ in both cases. Find $\mathbf{p}.$
\begin{pmatrix} 26/29 \\ 65/29 \end{pmatrix}
Find the sum of the values of $x$ such that $\cos^3 3x+ \cos^3 5x = 8 \cos^3 4x \cos^3 x$, where $x$ is measured in degrees and $100< x< 200.$
906
Find the average value of $0$, $2z$, $4z$, $8z$, and $16z$.
6z
There are $13$ positive integers greater than $\sqrt{15}$ and less than $\sqrt[3]{B}$ . What is the smallest integer value of $B$ ?
4097
In a high school with $500$ students, $40\%$ of the seniors play a musical instrument, while $30\%$ of the non-seniors do not play a musical instrument. In all, $46.8\%$ of the students do not play a musical instrument. How many non-seniors play a musical instrument?
154
If $a\in[0,\pi]$, $\beta\in\left[-\frac{\pi}{4},\frac{\pi}{4}\right]$, $\lambda\in\mathbb{R}$, and $\left(\alpha -\frac{\pi}{2}\right)^{3}-\cos \alpha -2\lambda =0$, $4\beta^{3}+\sin \beta \cos \beta +\lambda =0$, then the value of $\cos \left(\frac{\alpha}{2}+\beta \right)$ is ______.
\frac{ \sqrt{2}}{2}
While preparing balloons for Eva's birthday party, her mom bought 50 balloons and 1800cm³ of helium. One balloon needs 50cm³ to float high enough to touch the ceiling, and she can fill any remaining balloon with ordinary air. If she used up all of the helium and inflated every balloon, how many more balloons are touchi...
50cm³ will make one balloon touch the ceiling so 1800cm³ will make 1800/50 = <<1800/50=36>>36 balloons touch the ceiling There are 50 balloons in total so 50-36 = <<50-36=14>>14 balloons will not float since they were filled with ordinary air There are 36-14 = <<36-14=22>>22 more balloons touching the ceiling than not ...
Let $a_0 = 5/2$ and $a_k = a_{k-1}^2 - 2$ for $k \geq 1$. Compute \[ \prod_{k=0}^\infty \left(1 - \frac{1}{a_k} \right) \] in closed form.
\frac{3}{7}
The equation of a line is given by $Ax+By=0$. If we choose two different numbers from the set $\{1, 2, 3, 4, 5\}$ to be the values of $A$ and $B$ each time, then the number of different lines that can be obtained is     .
18
The height of a trapezoid, whose diagonals are mutually perpendicular, is 4. Find the area of the trapezoid if one of its diagonals is 5.
\frac{50}{3}
Notice that in the fraction $\frac{16}{64}$ we can perform a simplification as $\cancel{\frac{16}{64}}=\frac 14$ obtaining a correct equality. Find all fractions whose numerators and denominators are two-digit positive integers for which such a simplification is correct.
$\tfrac{19}{95}, \tfrac{16}{64}, \tfrac{11}{11}, \tfrac{26}{65}, \tfrac{22}{22}, \tfrac{33}{33} , \tfrac{49}{98}, \tfrac{44}{44}, \tfrac{55}{55}, \tfrac{66}{66}, \tfrac{77}{77}, \tfrac{88}{88} , \tfrac{99}{99}$
The average of the numbers $1, 2, 3, \dots, 149,$ and $x$ is $150x$. What is $x$?
\frac{11175}{22499}
Find the four roots of \[2x^4 + x^3 - 6x^2 + x + 2 = 0.\]Enter the four roots (counting multiplicity), separated by commas.
1, 1, -2, -\frac{1}{2}
Let $f(n)$ be the sum of the positive integer divisors of $n$. For how many values of $n$, where $1 \le n \le 25$, is $f(n)$ prime?
5
Given two random variables $X$ and $Y$, where $X\sim B(8, \frac{1}{2})$ and $Y\sim N(\mu, \sigma^2)$, find the probability $P(4 \leq Y \leq 8)$, given that $\mu = E(X)$ and $P(Y < 0) = 0.2$.
0.3
Danielle Bellatrix Robinson is organizing a poker tournament with 9 people. The tournament will have 4 rounds, and in each round the 9 players are split into 3 groups of 3. During the tournament, each player plays every other player exactly once. How many different ways can Danielle divide the 9 people into three group...
20160
Three clients are at the hairdresser, each paying their bill at the cash register. - The first client pays the same amount that is in the register and takes 10 reais as change. - The second client performs the same operation as the first. - The third client performs the same operation as the first two. Find the initi...
8.75
Convert $135_7$ to a base 10 integer.
75
Consider sequences that consist entirely of $A$'s and $B$'s and that have the property that every run of consecutive $A$'s has even length, and every run of consecutive $B$'s has odd length. Examples of such sequences are $AA$, $B$, and $AABAA$, while $BBAB$ is not such a sequence. How many such sequences have length 1...
172
Fully factor the following expression: $2x^2-8$
(2) (x+2) (x-2)
Let $ABC$ be a scalene triangle whose side lengths are positive integers. It is called *stable* if its three side lengths are multiples of 5, 80, and 112, respectively. What is the smallest possible side length that can appear in any stable triangle? *Proposed by Evan Chen*
20
The Cayley Corner Store sells three types of toys: Exes, Wyes and Zeds. All Exes are identical, all Wyes are identical, and all Zeds are identical. The mass of 2 Exes equals the mass of 29 Wyes. The mass of 1 Zed equals the mass of 16 Exes. The mass of 1 Zed equals the mass of how many Wyes?
232
The three roots of the cubic $ 30 x^3 - 50x^2 + 22x - 1$ are distinct real numbers strictly between $ 0$ and $ 1$. If the roots are $p$, $q$, and $r$, what is the sum \[ \frac{1}{1-p} + \frac{1}{1-q} +\frac{1}{1-r} ?\]
12
Find the maximum value of \[y = \tan \left( x + \frac{2 \pi}{3} \right) - \tan \left( x + \frac{\pi}{6} \right) + \cos \left( x + \frac{\pi}{6} \right)\]for $-\frac{5 \pi}{12} \le x \le -\frac{\pi}{3}.$
\frac{11 \sqrt{3}}{6}
Emilia writes down the numbers $5, x$, and 9. Valentin calculates the mean (average) of each pair of these numbers and obtains 7, 10, and 12. What is the value of $x$?
15
Six standard six-sided dice are rolled. We are told there is a pair and a three-of-a-kind, but no four-of-a-kind initially. The pair and the three-of-a-kind are set aside, and the remaining die is re-rolled. What is the probability that after re-rolling this die, at least four of the six dice show the same value?
\frac{1}{6}
A natural number \( N \) ends with the digit 5. A ninth-grader Dima found all its divisors and discovered that the sum of the two largest proper divisors is not divisible by the sum of the two smallest proper divisors. Find the smallest possible value of the number \( N \). A divisor of a natural number is called prope...
725
Suppose that $x$, $y$, and $z$ are complex numbers such that $xy = -80 - 320i$, $yz = 60$, and $zx = -96 + 24i$, where $i$ $=$ $\sqrt{-1}$. Then there are real numbers $a$ and $b$ such that $x + y + z = a + bi$. Find $a^2 + b^2$.
74
Given that point $P$ is on the line $y=2x+1$, and point $Q$ is on the curve $y=x+\ln x$, determine the minimum distance between points $P$ and $Q$.
\frac{2\sqrt{5}}{5}
Using only pennies, nickels, dimes, and quarters, what is the smallest number of coins Freddie would need so he could pay any amount of money less than a dollar?
10
What is the area of the portion of the circle defined by \(x^2 - 10x + y^2 = 9\) that lies above the \(x\)-axis and to the left of the line \(y = x-5\)?
4.25\pi
If $\displaystyle\prod_{i=6}^{2021} (1-\tan^2((2^i)^\circ))$ can be written in the form $a^b$ for positive integers $a,b$ with $a$ squarefree, find $a+b$ . *Proposed by Deyuan Li and Andrew Milas*
2018
Point $P$ is inside right triangle $\triangle ABC$ with $\angle B = 90^\circ$. Points $Q$, $R$, and $S$ are the feet of the perpendiculars from $P$ to $\overline{AB}$, $\overline{BC}$, and $\overline{CA}$, respectively. Given that $PQ = 2$, $PR = 3$, and $PS = 4$, what is $BC$?
6\sqrt{5}
On a 16 GB (gigabyte) capacity USB drive, 50% is already busy. Calculate the number of gigabytes still available.
We calculate 50% of 16 GB: 50/100 * 16 GB = 0.5 * 16 GB = <<50/100*16=8>>8 GB That leaves 16 GB - 8 GB = <<16-8=8>>8 GB available on this key. #### 8
Let $N=2^{(2^{2})}$ and $x$ be a real number such that $N^{(N^{N})}=2^{(2^{x})}$. Find $x$.
66
Triangle $ABC$ has side lengths $AB=4$, $BC=5$, and $CA=6$. Points $D$ and $E$ are on ray $AB$ with $AB<AD<AE$. The point $F \neq C$ is a point of intersection of the circumcircles of $\triangle ACD$ and $\triangle EBC$ satisfying $DF=2$ and $EF=7$. Then $BE$ can be expressed as $\tfrac{a+b\sqrt{c}}{d}$, where $a$, $b$...
32
Given points $A(\cos\alpha, \sin\alpha)$ and $B(\cos\beta, \sin\beta)$, where $\alpha, \beta$ are acute angles, and that $|AB| = \frac{\sqrt{10}}{5}$: (1) Find the value of $\cos(\alpha - \beta)$; (2) If $\tan \frac{\alpha}{2} = \frac{1}{2}$, find the values of $\cos\alpha$ and $\cos\beta$.
\frac{24}{25}
Given that the point $(4,7)$ is on the graph of $y=f(x)$, there is one point that must be on the graph of $2y=3f(4x)+5$. What is the sum of the coordinates of that point?
14
The function $\lfloor x\rfloor$ is defined as the largest integer less than or equal to $x$. For example, $\lfloor 5.67\rfloor = 5$, $\lfloor -\tfrac 14\rfloor = -1$, and $\lfloor 8\rfloor = 8$. What is the range of the function $$f(x) = \lfloor x\rfloor - x~?$$Express your answer in interval notation.
(-1,0]
Among the 200 natural numbers from 1 to 200, list the numbers that are neither multiples of 3 nor multiples of 5 in ascending order. What is the 100th number in this list?
187
Given a bag with 1 red ball and 2 black balls of the same size, two balls are randomly drawn. Let $\xi$ represent the number of red balls drawn. Calculate $E\xi$ and $D\xi$.
\frac{2}{9}
Circle $\Gamma$ is the incircle of $\triangle ABC$ and is also the circumcircle of $\triangle XYZ$. The point $X$ is on $\overline{BC}$, the point $Y$ is on $\overline{AB}$, and the point $Z$ is on $\overline{AC}$. If $\angle A=40^\circ$, $\angle B=60^\circ$, and $\angle C=80^\circ$, what is the measure of $\angle YZ...
60^\circ
If $\mathbf{a}$ and $\mathbf{b}$ are vectors such that $\|\mathbf{a}\| = 7$ and $\|\mathbf{b}\| = 11$, then find all possible values of $\mathbf{a} \cdot \mathbf{b}$. Submit your answer in interval notation.
[-77,77]
Find the cubic polynomial $p(x)$ such that $p(1) = -7,$ $p(2) = -9,$ $p(3) = -15,$ and $p(4) = -31.$
-x^3 + 4x^2 - 7x - 3
Cori is 3 years old today. In 5 years, she will be one-third the age of her aunt. How old is her aunt today?
In 5 years, Cori will be 3 + 5 = <<3+5=8>>8 years old. In 5 years, Cori’s aunt will be 8 x 3 = <<8*3=24>>24 years old. Today, her aunt is 24 - 5 = <<24-5=19>>19 years old. #### 19
We call any eight squares in a diagonal of a chessboard as a fence. The rook is moved on the chessboard in such way that he stands neither on each square over one time nor on the squares of the fences (the squares which the rook passes is not considered ones it has stood on). Then what is the maximum number of times wh...
47
Given a triangle ABC, let the lengths of the sides opposite to angles A, B, C be a, b, c, respectively. If a, b, c satisfy $a^2 + c^2 - b^2 = \sqrt{3}ac$, (1) find angle B; (2) if b = 2, c = $2\sqrt{3}$, find the area of triangle ABC.
2\sqrt{3}
There are 7 light bulbs arranged in a row. It is required to light up at least 3 of the bulbs, and adjacent bulbs cannot be lit at the same time. Determine the total number of different ways to light up the bulbs.
11
Given that $α∈\left( \frac{π}{2},π\right) $, and $\sin \left(π-α\right)+\cos \left(2π+α\right)= \frac{ \sqrt{2}}{3} $. Find the values of: $(1)\sin {α} -\cos {α} .$ $(2)\tan {α} $.
- \frac{9+4 \sqrt{2}}{7}
A small airplane can seat 10 people in first class, 30 in business class, and 50 in economy class seating. If economy class is half full, and business class and first class have the same number of people together as economy class, how many seats are unoccupied in business class if only three people on the flight have f...
There are 50 / 2 = <<50/2=25>>25 people in economy class. There are 25 people in business first and business class, so there are 25 - 3 = <<25-3=22>>22 in business class. Thus, there are 30 - 22 = <<30-22=8>>8 unoccupied seats in business class. #### 8
If $x - y = 6$ and $x + y = 12$, what is the value of $y$?
3
A convex polyhedron has for its faces 12 squares, 8 regular hexagons, and 6 regular octagons. At each vertex of the polyhedron one square, one hexagon, and one octagon meet. How many segments joining vertices of the polyhedron lie in the interior of the polyhedron rather than along an edge or a face?
840
Two cards are dealt at random from a standard deck of 52 cards. What is the probability that the first card is an Ace and the second card is a $\spadesuit$?
\dfrac{1}{52}
Adam's father deposited $2000 in the bank. It receives 8% interest paid throughout the year, and he withdraws the interest as soon as it is deposited. How much will Adam’s father have, including his deposit and the interest received after 2 and a half years?
The annual interest is 2000 * 8/100 = $<<2000*8/100=160>>160. Interest for two and a half years is 160 * 2.5 = $<<160*2.5=400>>400. So, Adam's father will have 2000 + 400 = $<<2000+400=2400>>2400 after 2 and a half years. #### 2400
A round-robin tennis tournament consists of each player playing every other player exactly once. How many matches will be held during an 8-person round-robin tennis tournament?
28
Let a $9$ -digit number be balanced if it has all numerals $1$ to $9$ . Let $S$ be the sequence of the numerals which is constructed by writing all balanced numbers in increasing order consecutively. Find the least possible value of $k$ such that any two subsequences of $S$ which has consecutive $k$ numeral...
17
Let $S = \{2^0,2^1,2^2,\ldots,2^{10}\}$. Consider all possible positive differences of pairs of elements of $S$. Let $N$ be the sum of all of these differences. Find the remainder when $N$ is divided by $1000$.
398
Color the vertices of a quadrilateral pyramid so that the endpoints of each edge are different colors. If there are only 5 colors available, what is the total number of distinct coloring methods?
420
The number $n$ is a prime number between 20 and 30. If you divide $n$ by 8, the remainder is 5. What is the value of $n$?
29
The lunchroom is full of students: 40% are girls and the remainder are boys. There are 2 monitors for every 15 students. There are 8 monitors. Every boy drinks, on average, 1 carton of milk, and every girl drinks, on average, 2 cartons of milk. How many total cartons of milk are consumed by the students in the lunchroo...
There is 1 monitor for every fifteen students because 30 / 2 = <<30/2=15>>15 There are 120 students because 8 x 15 = <<8*15=120>>120 60% of the lunchroom is boys because 100 - 40 = <<100-40=60>>60 There are 72 boys because 120 x .6 = <<120*.6=72>>72 There are 48 girls because 120 x .4 = <<120*.4=48>>48 The boys drink 7...
For an operations manager job at a company, a person with a degree earns three times the amount paid to a diploma holder for the same position. How much will Jared earn from the company in a year after graduating with a degree if the pay for a person holding a diploma certificate is $4000 per month?
Since the pay for a person holding a degree is three times the amount paid for a diploma holder, Jared will earn 3*$4000 = $<<4000*3=12000>>12000 per month. In a year with 12 months, Jared will earn a total of 12*12000 = <<12*12000=144000>>144000 #### 144000
John buys a box of 40 light bulbs. He uses 16 of them and then gives half of what is left to a friend. How many does he have left?
He had 40-16=<<40-16=24>>24 left after using some Then after giving some away he is left with 24/2=<<24/2=12>>12 #### 12
Two different points, $C$ and $D$, lie on the same side of line $AB$ so that $\triangle ABC$ and $\triangle BAD$ are congruent with $AB = 9$, $BC=AD=10$, and $CA=DB=17$. The intersection of these two triangular regions has area $\tfrac mn$, where $m$ and $n$ are relatively prime positive integers. Find $m+n$.
59
Let $a,$ $b,$ and $c$ be angles such that \begin{align*} \sin a &= \cot b, \\ \sin b &= \cot c, \\ \sin c &= \cot a. \end{align*} Find the largest possible value of $\cos a.$
\sqrt{\frac{3 - \sqrt{5}}{2}}
A frequency distribution of the scores for Mr. Sampson's algebra class is shown. What percent of the class received a score in the $60\%$-$69\%$ range? \begin{tabular}{|c|c|} Test Scores & Frequencies\\ \hline $90\% - 100\%$& IIII\\ $80\% - 89\%$& IIII IIII\\ $70\% - 79\%$& IIII II\\ $60\% - 69\%$ & IIII I\\ Below $60\...
20\%
A rectangular box $Q$ is inscribed in a sphere of radius $s$. The surface area of $Q$ is 576, and the sum of the lengths of its 12 edges is 168. Determine the radius $s$.
3\sqrt{33}
In the adjoining figure the five circles are tangent to one another consecutively and to the lines $L_1$ and $L_2$. If the radius of the largest circle is $18$ and that of the smallest one is $8$, then the radius of the middle circle is
12
Three different 6th grade classes are combining for a square dancing unit. If possible, the teachers would like each male student to partner with a female student for the unit. The first class has 17 males and 13 females, while the second class has 14 males and 18 females, and the third class has 15 males and 17 fema...
Combining the three classes, there are 17 + 14 + 15 = <<17+14+15=46>>46 male students. Similarly, there are 13 + 18 + 17 = <<13+18+17=48>>48 female students. Thus, there are 48-46 = <<48-46=2>>2 students who cannot partner with a student of the opposite gender. #### 2
The functions $p(x),$ $q(x),$ and $r(x)$ are all invertible. We set \[f = q \circ p \circ r.\]Which is the correct expression for $f^{-1}$? A. $r^{-1} \circ q^{-1} \circ p^{-1}$ B. $p^{-1} \circ q^{-1} \circ r^{-1}$ C. $r^{-1} \circ p^{-1} \circ q^{-1}$ D. $q^{-1} \circ p^{-1} \circ r^{-1}$ E. $q^{-1} \circ r^{-1...
\text{C}
A dealer sold 200 cars, and the data for some of those sales are recorded in this table. If the rest of the cars she sold were Hondas, how many Hondas did she sell? \begin{tabular}{ |c | c|} \hline \textbf{Type of Car} & \textbf{$\%$ of Total Cars Sold} \\ \hline Audi & $15\%$ \\ \hline Toyota & $22\%$ \\ \hline Acura...
70
Given that \(7^{-1} \equiv 55 \pmod{101}\), find \(49^{-1} \pmod{101}\), as a residue modulo 101. (Answer should be between 0 and 100, inclusive.)
96
Given the derivative of the function $f(x)$ is $f'(x) = 2 + \sin x$, and $f(0) = -1$. The sequence $\{a_n\}$ is an arithmetic sequence with a common difference of $\frac{\pi}{4}$. If $f(a_2) + f(a_3) + f(a_4) = 3\pi$, calculate $\frac{a_{2016}}{a_{2}}$.
2015
The circumference of a circle $A$ is 60 feet. How many feet long is $\widehat{BC}$? [asy] import markers; import olympiad; import geometry; import graph; size(150); defaultpen(linewidth(0.9)); draw(Circle(origin,1)); draw(dir(90)--origin--dir(30)); label("$B$",dir(90),N); label("$A$",origin,S); label("$C$",dir(30),E);...
10
There is a house at the center of a circular field. From it, 6 straight roads radiate, dividing the field into 6 equal sectors. Two geologists start their journey from the house, each choosing a road at random and traveling at a speed of 4 km/h. Determine the probability that the distance between them after an hour is ...
0.5
Evaluate $\log_3 27\sqrt3$. Express your answer as an improper fraction.
\frac72