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The expressions $A$ = $1 \times 2 + 3 \times 4 + 5 \times 6 + \cdots + 37 \times 38 + 39$ and $B$ = $1 + 2 \times 3 + 4 \times 5 + \cdots + 36 \times 37 + 38 \times 39$ are obtained by writing multiplication and addition operators in an alternating pattern between successive integers. Find the positive difference betwe...
722
We have \[|A-B|=|1+3(4-2)+5(6-4)+ \cdots + 37(38-36)-39(1-38)|\]\[\implies |2(1+3+5+7+ \cdots +37)-1-39(37)|\]\[\implies |361(2)-1-39(37)|=|722-1-1443|=|-722|\implies \boxed{722}\]
0.6875
4,989.625
4,097.272727
6,952.8
How many positive multiples of 3 that are less than 150 have a units digit of 3 or 6?
10
0.75
5,179.3125
5,395.166667
4,531.75
What is the sum and product of the distinct prime factors of 420?
210
1
1,508.4375
1,508.4375
-1
The World Cup football tournament is held in Brazil, and the host team Brazil is in group A. In the group stage, the team plays a total of 3 matches. The rules stipulate that winning one match scores 3 points, drawing one match scores 1 point, and losing one match scores 0 points. If the probability of Brazil winning, ...
0.5
0
8,027.0625
-1
8,027.0625
What is $ 6 \div 3 - 2 - 8 + 2 \cdot 8$?
8
1
1,185.1875
1,185.1875
-1
A set of positive integers is said to be pilak if it can be partitioned into 2 disjoint subsets \(F\) and \(T\), each with at least 2 elements, such that the elements of \(F\) are consecutive Fibonacci numbers, and the elements of \(T\) are consecutive triangular numbers. Find all positive integers \(n\) such that the ...
30
0
8,192
-1
8,192
Half of the blue flowers are tulips, five sixths of the yellow flowers are daisies, and four fifths of the flowers are yellow. What percent of the flowers are tulips?
23.3
0
3,282.9375
-1
3,282.9375
There are 20 cards, each with a number from 1 to 20. These cards are placed in a box, and 4 people each draw one card without replacement. The two people who draw the smaller numbers form one group, and the two people who draw the larger numbers form another group. If two people draw the numbers 5 and 14, what is the p...
7/51
0.5625
6,236.9375
5,361.222222
7,362.857143
A running competition on an unpredictable distance is conducted as follows. On a circular track with a length of 1 kilometer, two points \( A \) and \( B \) are randomly selected (using a spinning arrow). The athletes then run from \( A \) to \( B \) along the shorter arc. Find the median value of the length of this ar...
0.25
0.1875
4,968.25
4,962
4,969.692308
Rebecca has four resistors, each with resistance 1 ohm . Every minute, she chooses any two resistors with resistance of $a$ and $b$ ohms respectively, and combine them into one by one of the following methods: - Connect them in series, which produces a resistor with resistance of $a+b$ ohms; - Connect them in parallel,...
15
Let $R_{n}$ be the set of all possible resistances using exactly $n$ 1-ohm circuit segments (without shorting any of them), then we get $R_{n}=\bigcup_{i=1}^{n-1}\left(\left\{a+b \mid a \in R_{i}, b \in R_{n-i}\right\} \cup\left\{\left.\frac{a b}{a+b} \right\rvert\, a \in R_{i}, b \in R_{n-i}\right\}\right)$, starting ...
0
8,192
-1
8,192
What is the smallest positive integer with exactly 20 positive divisors?
240
0.875
6,508.75
6,268.285714
8,192
Given the six whole numbers 10-15, compute the largest possible value for the sum, S, of the three numbers on each side of the triangle.
39
0
7,359
-1
7,359
John is planning to fence a rectangular garden such that the area is at least 150 sq. ft. The length of the garden should be 20 ft longer than its width. Additionally, the total perimeter of the garden must not exceed 70 ft. What should the width, in feet, be?
-10 + 5\sqrt{10}
0
6,898.5625
-1
6,898.5625
Let $S = \{1, 2, \ldots, 2005\}$. If any set of $n$ pairwise coprime numbers from $S$ always contains at least one prime number, find the smallest value of $n$.
16
0
8,047.5625
-1
8,047.5625
Rectangles $R_1$ and $R_2,$ and squares $S_1, S_2,$ and $S_3,$ shown below, combine to form a rectangle that is 3322 units wide and 2020 units high. What is the side length of $S_2$ in units?
651
1. **Assign Variables:** Let the side length of square $S_2$ be $s$. Let the shorter side length of rectangles $R_1$ and $R_2$ be $r$. 2. **Analyze the Geometry:** From the problem's description and the arrangement of the shapes, we can deduce that the total height of the large rectangle is formed by stacking $...
0
7,923.1875
-1
7,923.1875
Starting at $(0,0),$ an object moves in the coordinate plane via a sequence of steps, each of length one. Each step is to the left, right, up, or down, all four equally likely. Let $q$ be the probability that the object reaches $(3,3)$ in eight or fewer steps. Write $q$ in the form $a/b$, where $a$ and $b$ are relative...
4151
0.0625
7,433.375
5,063
7,591.4
Let $z = \cos \frac{4 \pi}{7} + i \sin \frac{4 \pi}{7}.$ Compute \[\frac{z}{1 + z^2} + \frac{z^2}{1 + z^4} + \frac{z^3}{1 + z^6}.\]
-2
0.0625
8,145.75
7,452
8,192
Square A has side lengths each measuring $x$ inches. Square B has side lengths each measuring $4x$ inches. What is the ratio of the area of the smaller square to the area of the larger square? Express your answer as a common fraction.
\frac{1}{16}
1
1,021.5
1,021.5
-1
Find all solutions to the equation $\!\sqrt{2-3z} = 9$. Express your answer as a common fraction.
-\frac{79}{3}
1
1,519.1875
1,519.1875
-1
Given a circle with center \(O\) and radius \(OD\) perpendicular to chord \(AB\), intersecting \(AB\) at point \(C\). Line segment \(AO\) is extended to intersect the circle at point \(E\). If \(AB = 8\) and \(CD = 2\), calculate the area of \(\triangle BCE\).
12
0.6875
5,559.125
4,966.272727
6,863.4
What is the greatest possible value of $x$ for the equation $$\left(\frac{4x-16}{3x-4}\right)^2+\left(\frac{4x-16}{3x-4}\right)=12?$$
2
1
2,079.875
2,079.875
-1
One hundred concentric circles with radii $1, 2, 3, \dots, 100$ are drawn in a plane. The interior of the circle of radius $1$ is colored red, and each region bounded by consecutive circles is colored either red or green, with no two adjacent regions the same color. The ratio of the total area of the green regions to t...
301
We want to find $\frac{\sum\limits_{n=1}^{50} (4n-1)\pi}{10000\pi}=\frac{\sum\limits_{n=1}^{50} (4n-1)}{10000}=\frac{(\sum\limits_{n=1}^{50} (4n) )-50}{10000}=\frac{101}{200} \rightarrow 101+200=\boxed{301}$
0.6875
4,543.875
3,594.363636
6,632.8
Simplify $\dfrac{111}{9999} \cdot 33.$
\dfrac{37}{101}
0.9375
4,249.75
4,105.066667
6,420
Two walls and the ceiling of a room meet at right angles at point $P.$ A fly is in the air one meter from one wall, eight meters from the other wall, and nine meters from point $P$. How many meters is the fly from the ceiling?
4
1. **Identify the coordinates of the fly and point $P$:** - Let's assume point $P$ is at the origin $(0,0,0)$ of a three-dimensional coordinate system. - The fly is 1 meter from one wall, 8 meters from another wall, and 9 meters from point $P$. We can assume the fly is at point $(1, 8, z)$, where $z$ is the dista...
0.875
4,919.625
4,452.142857
8,192
Evaluate \[\begin{vmatrix} 0 & \sin \alpha & -\cos \alpha \\ -\sin \alpha & 0 & \sin \beta \\ \cos \alpha & -\sin \beta & 0 \end{vmatrix}.\]
0
0.6875
4,552.875
2,898.727273
8,192
In a triangle $\triangle ABC$, $\angle A = 45^\circ$ and $\angle B = 60^\circ$. A line segment $DE$, with $D$ on $AB$ and $\angle ADE = 30^\circ$, divides $\triangle ABC$ into two pieces of equal area. Determine the ratio $\frac{AD}{AB}$. A) $\frac{\sqrt{3}}{4}$ B) $\frac{\sqrt{6} + \sqrt{2}}{4}$ C) $\frac{1}{4}$ D) $\...
\frac{\sqrt{6} + \sqrt{2}}{4}
0
8,192
-1
8,192
Find the area of triangle $DEF$ below, where $DF = 8$ and $\angle D = 45^\circ$. [asy] unitsize(1inch); pair D,E,F; D = (0,0); E= (sqrt(2),0); F = (0,sqrt(2)); draw (D--E--F--D,linewidth(0.9)); draw(rightanglemark(E,D,F,3)); label("$D$",D,S); label("$E$",E,S); label("$F$",F,N); label("$8$",F/2,W); label("$45^\circ$",(...
32
0.5625
6,504.5
5,754
7,469.428571
Suppose two distinct integers are chosen from between 5 and 17, inclusive. What is the probability that their product is odd?
\dfrac{7}{26}
0.9375
1,621.0625
1,624
1,577
The graph of the parabola $x = 2y^2 - 6y + 3$ has an $x$-intercept $(a,0)$ and two $y$-intercepts $(0,b)$ and $(0,c)$. Find $a + b + c$.
6
1
2,120.4375
2,120.4375
-1
Let the function \( f(x) = x^3 + a x^2 + b x + c \), where \( a \), \( b \), and \( c \) are non-zero integers. If \( f(a) = a^3 \) and \( f(b) = b^3 \), then the value of \( c \) is:
16
0.6875
6,213.5625
5,314.272727
8,192
We have a $6 \times 6$ square, partitioned into 36 unit squares. We select some of these unit squares and draw some of their diagonals, subject to the condition that no two diagonals we draw have any common points. What is the maximal number of diagonals that we can draw?
18
0.1875
7,750.5625
5,837.666667
8,192
The diagram shows a square and a regular decagon that share an edge. One side of the square is extended to meet an extended edge of the decagon. What is the value of \( x \)? A) 15 B) 18 C) 21 D) 24 E) 27
18
0
7,920.3125
-1
7,920.3125
Suppose we have 12 dogs and need to divide them into three groups: one with 4 dogs, one with 5 dogs, and one with 3 dogs. Determine how many ways the groups can be formed if Rocky, a notably aggressive dog, must be in the 4-dog group, and Bella must be in the 5-dog group.
4200
0.5
6,892.625
5,803.125
7,982.125
Given that Charlie estimates 80,000 fans in Chicago, Daisy estimates 70,000 fans in Denver, and Ed estimates 65,000 fans in Edmonton, and given the actual attendance in Chicago is within $12\%$ of Charlie's estimate, Daisy's estimate is within $15\%$ of the actual attendance in Denver, and the actual attendance in Edmo...
29000
0.3125
5,913.5625
4,822.6
6,409.454545
Given that points $P$ and $Q$ are on the circle $x^2 + (y-6)^2 = 2$ and the ellipse $\frac{x^2}{10} + y^2 = 1$, respectively, what is the maximum distance between $P$ and $Q$? A) $5\sqrt{2}$ B) $\sqrt{46} + \sqrt{2}$ C) $7 + \sqrt{2}$ D) $6\sqrt{2}$
6\sqrt{2}
0
8,192
-1
8,192
The graphs $y = 3(x-h)^2 + j$ and $y = 2(x-h)^2 + k$ have $y$-intercepts of $2013$ and $2014$, respectively, and each graph has two positive integer $x$-intercepts. Find $h$.
36
0.625
6,211.5625
5,023.3
8,192
The letter T is formed by placing a $2\:\text{inch} \times 6\:\text{inch}$ rectangle vertically and a $2\:\text{inch} \times 4\:\text{inch}$ rectangle horizontally across the top center of the vertical rectangle. What is the perimeter of the T, in inches?
24
0.125
7,724.4375
5,934.5
7,980.142857
There are 10 boys, each with different weights and heights. For any two boys $\mathbf{A}$ and $\mathbf{B}$, if $\mathbf{A}$ is heavier than $\mathbf{B}$, or if $\mathbf{A}$ is taller than $\mathbf{B}$, we say that " $\mathrm{A}$ is not inferior to B". If a boy is not inferior to the other 9 boys, he is called a "strong...
10
0
8,098.25
-1
8,098.25
Makarla attended two meetings during her $9$-hour work day. The first meeting took $45$ minutes and the second meeting took twice as long. What percent of her work day was spent attending meetings?
25
1. **Calculate the total workday time in minutes**: Makarla's workday is 9 hours long. Since there are 60 minutes in an hour, the total number of minutes in her workday is: \[ 9 \times 60 = 540 \text{ minutes} \] 2. **Determine the duration of the second meeting**: The first meeting took 45 minutes and...
0.9375
2,101.9375
1,695.933333
8,192
The country Omega grows and consumes only vegetables and fruits. It is known that in 2014, 1200 tons of vegetables and 750 tons of fruits were grown in Omega. In 2015, 900 tons of vegetables and 900 tons of fruits were grown. During the year, the price of one ton of vegetables increased from 90,000 to 100,000 rubles, a...
-9.59
0.3125
4,602.6875
4,613.6
4,597.727273
For the power of _n_ of a natural number _m_ greater than or equal to 2, the following decomposition formula is given: 2<sup>2</sup> = 1 + 3, 3<sup>2</sup> = 1 + 3 + 5, 4<sup>2</sup> = 1 + 3 + 5 + 7… 2<sup>3</sup> = 3 + 5, 3<sup>3</sup> = 7 + 9 + 11… 2<sup>4</sup> = 7 + 9… According to this pattern, the third n...
125
0
8,192
-1
8,192
Given a function $f(x)$ that satisfies the functional equation $f(x) = f(x+1) - f(x+2)$ for all $x \in \mathbb{R}$. When $x \in (0,3)$, $f(x) = x^2$. Express the value of $f(2014)$ using the functional equation.
-1
0.3125
6,849.125
4,857
7,754.636364
The side \( AB \) of triangle \( ABC \) is longer than side \( AC \), and \(\angle A = 40^\circ\). Point \( D \) lies on side \( AB \) such that \( BD = AC \). Points \( M \) and \( N \) are the midpoints of segments \( BC \) and \( AD \) respectively. Find the angle \( \angle BNM \).
20
0.875
5,252.5
4,832.571429
8,192
Calculate the sum of the distances from one vertex of a rectangle with sides of lengths $3$ and $5$ to the midpoints of each of the sides of the rectangle. A) $11.2$ B) $12.4$ C) $13.1$ D) $14.5$ E) $15.2$
13.1
0
5,463.9375
-1
5,463.9375
Let $f(x)=x^{3}-3x$. Compute the number of positive divisors of $$\left\lfloor f\left(f\left(f\left(f\left(f\left(f\left(f\left(f\left(\frac{5}{2}\right)\right)\right)\right)\right)\right)\right)\right)\right)\rfloor$$ where $f$ is applied 8 times.
6562
Note that $f\left(y+\frac{1}{y}\right)=\left(y+\frac{1}{y}\right)^{3}-3\left(y+\frac{1}{y}\right)=y^{3}+\frac{1}{y^{3}}$. Thus, $f\left(2+\frac{1}{2}\right)=2^{3}+\frac{1}{2^{3}}$, and in general $f^{k}\left(2+\frac{1}{2}\right)=2^{3^{k}}+\frac{1}{2^{3^{k}}}$, where $f$ is applied $k$ times. It follows that we just nee...
0.25
7,962.9375
7,275.75
8,192
Let \(p\), \(q\), \(r\), \(s\), and \(t\) be positive integers such that \(p+q+r+s+t=3015\) and let \(N\) be the largest of the sums \(p+q\), \(q+r\), \(r+s\), and \(s+t\). What is the smallest possible value of \(N\)?
1508
0
6,964.5625
-1
6,964.5625
Solve $\log_4 x + \log_2 x^2 = 10$.
16
1
2,445.125
2,445.125
-1
For how many digits $C$ is the positive three-digit number $1C3$ a multiple of 3?
3
1
2,029.4375
2,029.4375
-1
The arithmetic mean (average) of the first $n$ positive integers is:
\frac{n+1}{2}
1. **Identify the sum of the first $n$ positive integers**: The sum of the first $n$ positive integers can be calculated using the formula for the sum of an arithmetic series. The formula for the sum of the first $n$ positive integers (also known as the $n$-th triangular number) is: \[ S_n = \frac{n(n+1)}{2} \...
1
1,510.625
1,510.625
-1
Two sides of a right triangle have the lengths 4 and 5. What is the product of the possible lengths of the third side? Express the product as a decimal rounded to the nearest tenth.
19.2
1
2,418
2,418
-1
An entry in a grid is called a saddle point if it is the largest number in its row and the smallest number in its column. Suppose that each cell in a $3 \times 3$ grid is filled with a real number, each chosen independently and uniformly at random from the interval $[0,1]$. Compute the probability that this grid has at...
\frac{3}{10}
With probability 1, all entries of the matrix are unique. If this is the case, we claim there can only be one saddle point. To see this, suppose $A_{i j}$ and $A_{k l}$ are both saddle points. They cannot be in the same row, since they cannot both be the greatest number in the same row, and similarly they cannot be in ...
0
8,192
-1
8,192
Given sets $A=\{2,3,4\}$ and $B=\{a+2,a\}$, if $A \cap B = B$, find $A^cB$ ___.
\{3\}
0.875
1,942.875
1,876.857143
2,405
What is the largest perfect square factor of 1512?
36
1
3,351.8125
3,351.8125
-1
In the side face $A A^{\prime} B^{\prime} B$ of a unit cube $A B C D - A^{\prime} B^{\prime} C^{\prime} D^{\prime}$, there is a point $M$ such that its distances to the two lines $A B$ and $B^{\prime} C^{\prime}$ are equal. What is the minimum distance from a point on the trajectory of $M$ to $C^{\prime}$?
\frac{\sqrt{5}}{2}
0
8,077.5
-1
8,077.5
The number 519 is formed using the digits 5, 1, and 9. The three digits of this number are rearranged to form the largest possible and then the smallest possible three-digit numbers. What is the difference between these largest and smallest numbers?
792
1
324.6875
324.6875
-1
Find the number of solutions to \[\cos 4x + \cos^2 3x + \cos^3 2x + \cos^4 x = 0\]for $-\pi \le x \le \pi.$
10
0.0625
8,039.6875
5,774
8,190.733333
Find the largest integer \( a \) such that the expression \[ a^2 - 15a - (\tan x - 1)(\tan x + 2)(\tan x + 5)(\tan x + 8) \] is less than 35 for all values of \( x \in (-\pi/2, \pi/2) \).
10
0.5625
6,719.3125
5,573.888889
8,192
Let $S$ be the set \{1,2, \ldots, 2012\}. A perfectutation is a bijective function $h$ from $S$ to itself such that there exists an $a \in S$ such that $h(a) \neq a$, and that for any pair of integers $a \in S$ and $b \in S$ such that $h(a) \neq a, h(b) \neq b$, there exists a positive integer $k$ such that $h^{k}(a)=b...
2
Note that both $f$ and $g$, when written in cycle notation, must contain exactly one cycle that contains more than 1 element. Assume $f$ has $k$ fixed points, and that the other $2012-k$ elements form a cycle, (of which there are (2011 - $k$ )! ways). Then note that if $f$ fixes $a$ then $f(g(a))=g(f(a))=g(a)$ implies ...
0
7,671.75
-1
7,671.75
Compute the perimeter of the triangle that has area $3-\sqrt{3}$ and angles $45^\circ$ , $60^\circ$ , and $75^\circ$ .
3\sqrt{2} + 2\sqrt{3} - \sqrt{6}
0.0625
7,446.9375
7,325
7,455.066667
The number of positive integers less than $1000$ divisible by neither $5$ nor $7$ is:
686
1. **Count the integers divisible by 5:** The number of positive integers less than $1000$ that are divisible by $5$ can be calculated using the floor function: \[ \left\lfloor \frac{999}{5} \right\rfloor = 199 \] This is because $999$ is the largest number less than $1000$, and dividing it by $5$ and ta...
0.9375
3,948.625
3,665.733333
8,192
It is known that there exists a natural number \( N \) such that \( (\sqrt{3}-1)^{N} = 4817152 - 2781184 \cdot \sqrt{3} \). Find \( N \).
16
0
8,192
-1
8,192
The lengths of the sides of a triangle are consecutive integers, and the largest angle is twice the smallest angle. Find the cosine of the smallest angle.
\frac{3}{4}
0.5625
6,389.875
4,988.222222
8,192
On the sides of a unit square, points \( K, L, M, \) and \( N \) are marked such that line \( KM \) is parallel to two sides of the square, and line \( LN \) is parallel to the other two sides of the square. The segment \( KL \) cuts off a triangle from the square with a perimeter of 1. What is the area of the triangle...
\frac{1}{4}
0
8,192
-1
8,192
Athletes A, B, and C, along with 4 volunteers, are to be arranged in a line. If A and B are next to each other and C is not at either end, determine the number of different ways to arrange them.
960
0.375
7,603.3125
6,801.5
8,084.4
Let $S$ be a set of $6$ integers taken from $\{1,2,\dots,12\}$ with the property that if $a$ and $b$ are elements of $S$ with $a<b$, then $b$ is not a multiple of $a$. What is the least possible value of an element in $S$?
4
To solve this problem, we need to ensure that no element in the set $S$ is a multiple of any other element in $S$. We start by partitioning the set $\{1, 2, \dots, 12\}$ into subsets where each element in a subset is a multiple of the smallest element in that subset. This partitioning helps us to easily identify and av...
0
8,192
-1
8,192
Given the set $H$ defined by the points $(x,y)$ with integer coordinates, $2\le|x|\le8$, $2\le|y|\le8$, calculate the number of squares of side at least $5$ that have their four vertices in $H$.
14
0
8,192
-1
8,192
Given the function $f\left(x\right)=ax^{2}-bx-1$, sets $P=\{1,2,3,4\}$, $Q=\{2,4,6,8\}$, if a number $a$ and a number $b$ are randomly selected from sets $P$ and $Q$ respectively to form a pair $\left(a,b\right)$.<br/>$(1)$ Let event $A$ be "the monotonically increasing interval of the function $f\left(x\right)$ is $\l...
\frac{11}{16}
0.6875
6,925.0625
6,349.181818
8,192
A three-quarter sector of a circle of radius $4$ inches together with its interior can be rolled up to form the lateral surface area of a right circular cone by taping together along the two radii shown. What is the volume of the cone in cubic inches?
$3 \pi \sqrt{7}$
1. **Understanding the Geometry of the Problem**: The problem states that a three-quarter sector of a circle with radius $4$ inches is rolled up to form a cone. The sector's arc length becomes the circumference of the cone's base, and the radius of the sector becomes the slant height of the cone. 2. **Calculating ...
0
1,919
-1
1,919
Two people are flipping a coin: one flipped it 10 times, and the other flipped it 11 times. Find the probability that the second person gets more heads than the first person.
1/2
0
8,179.375
-1
8,179.375
A wizard is crafting a magical elixir. For this, he requires one of four magical herbs and one of six enchanted gems. However, one of the gems cannot be used with three of the herbs. Additionally, another gem can only be used if it is paired with one specific herb. How many valid combinations can the wizard use to prep...
18
0.0625
6,867.0625
5,275
6,973.2
How many perfect squares less than 1000 have a ones digit of 2, 3 or 4?
6
0.625
4,377
3,885
5,197
Driving at a constant speed, Sharon usually takes $180$ minutes to drive from her house to her mother's house. One day Sharon begins the drive at her usual speed, but after driving $\frac{1}{3}$ of the way, she hits a bad snowstorm and reduces her speed by $20$ miles per hour. This time the trip takes her a total of $2...
135
1. **Define Variables:** Let the total distance from Sharon's house to her mother's house be $x$ miles. 2. **Calculate Speeds:** Sharon's usual speed is $\frac{x}{180}$ miles per minute, since she normally takes 180 minutes to cover $x$ miles. 3. **Distance and Speed Adjustments:** After driving $\frac{1}{3...
0.875
2,840.5625
2,076.071429
8,192
Let $n>1$ be a positive integer. Ana and Bob play a game with other $n$ people. The group of $n$ people form a circle, and Bob will put either a black hat or a white one on each person's head. Each person can see all the hats except for his own one. They will guess the color of his own hat individually. Before Bob dis...
\left\lfloor \frac{n-1}{2} \right\rfloor
Given a group of \( n \) people forming a circle, Ana and Bob play a strategy-based game where Bob assigns each person either a black hat or a white hat. The challenge is that each person can see every other hat except their own. The goal is for Ana to devise a strategy to maximize the number of correct guesses about ...
0
7,679.8125
-1
7,679.8125
Nathaniel and Obediah play a game in which they take turns rolling a fair six-sided die and keep a running tally of the sum of the results of all rolls made. A player wins if, after he rolls, the number on the running tally is a multiple of 7. Play continues until either player wins, or else inde nitely. If Nathaniel g...
5/11
0
8,192
-1
8,192
Compute the square of 1017 without a calculator.
1034289
0.5625
2,621.8125
2,547.333333
2,717.571429
Simplify $\dfrac{123}{999} \cdot 27.$
\dfrac{123}{37}
1
4,399.125
4,399.125
-1
On an island, there live three tribes: knights, who always tell the truth; liars, who always lie; and tricksters, who sometimes tell the truth and sometimes lie. At a round table sit 100 representatives of these tribes. Each person at the table said two sentences: 1) "To my left sits a liar"; 2) "To my right sits a tr...
25
0.0625
8,049.0625
5,905
8,192
Jim starts with a positive integer $n$ and creates a sequence of numbers. Each successive number is obtained by subtracting the largest possible integer square less than or equal to the current number until zero is reached. For example, if Jim starts with $n = 55$, then his sequence contains $5$ numbers: $\begin{array...
3
To solve this problem, we need to construct a sequence of numbers starting from $N$ such that the sequence has exactly 8 numbers, including $N$ and $0$. Each number in the sequence is obtained by subtracting the largest perfect square less than or equal to the current number. We start from the last step and work our w...
0
8,192
-1
8,192
Given the increasing sequence of positive integers \(a_{1}, a_{2}, a_{3}, \cdots\) satisfies the recurrence relation \(a_{n+2} = a_{n} + a_{n+1}\) for \(n \geq 1\), and \(a_{7} = 120\), find the value of \(a_{8}\).
194
1
3,133.3125
3,133.3125
-1
Given the function $f(x)=2\cos ^{2} \frac{x}{2}- \sqrt {3}\sin x$. (I) Find the smallest positive period and the range of the function; (II) If $a$ is an angle in the second quadrant and $f(a- \frac {π}{3})= \frac {1}{3}$, find the value of $\frac {\cos 2a}{1+\cos 2a-\sin 2a}$.
\frac{1-2\sqrt{2}}{2}
0
6,176.0625
-1
6,176.0625
From the 20 natural numbers 1, 2, 3, ..., 20, if three numbers are randomly selected and their sum is an even number greater than 10, then there are $\boxed{\text{answer}}$ such sets of numbers.
563
0.5
6,493.25
4,794.5
8,192
The diagram shows a segment of a circle such that \( CD \) is the perpendicular bisector of the chord \( AB \). Given that \( AB = 16 \) and \( CD = 4 \), find the diameter of the circle.
20
0.0625
4,906.625
5,016
4,899.333333
In this final problem, a ball is again launched from the vertex of an equilateral triangle with side length 5. In how many ways can the ball be launched so that it will return again to a vertex for the first time after 2009 bounces?
502
We will use the same idea as in the previous problem. We first note that every vertex of a triangle can be written uniquely in the form $a(5,0)+b\left(\frac{5}{2}, \frac{5 \sqrt{3}}{2}\right)$, where $a$ and $b$ are non-negative integers. Furthermore, if a ball ends at $a(5,0)+b\left(\frac{5}{2}, \frac{5 \sqrt{3}}{2}\r...
0
7,771
-1
7,771
Find $\cos B$ and $\sin A$ in the following right triangle where side $AB = 15$ units, and side $BC = 20$ units.
\frac{3}{5}
0
5,271.8125
-1
5,271.8125
The number of children in the families $A$, $B$, $C$, $D$, and $E$ are as shown in the table below: | | $A$ | $B$ | $C$ | $D$ | $E$ | |---------|-----|-----|-----|-----|-----| | Boys | $0$ | $1$ | $0$ | $1$ | $1$ | | Girls | $0$ | $0$ | $1$ | $1$ | $2$ | $(1)$ If a child is randomly selected from these c...
\frac{6}{5}
0.625
3,288.5625
3,310.1
3,252.666667
Let $x$ and $y$ be positive real numbers such that \[\frac{1}{x + 2} + \frac{1}{y + 2} = \frac{1}{3}.\]Find the minimum value of $x + 2y.$
3 + 6 \sqrt{2}
0.5625
6,900.0625
6,049.666667
7,993.428571
On November 15, a dodgeball tournament took place. In each game, two teams competed. A win was awarded 15 points, a tie 11 points, and a loss 0 points. Each team played against every other team once. At the end of the tournament, the total number of points accumulated was 1151. How many teams participated?
12
0.375
7,447.6875
6,207.166667
8,192
In a circle with center $O$, $AD$ is a diameter, $ABC$ is a chord, $BO = 6$, and $\angle ABO = \text{arc } CD = 45^\circ$. Find the length of $BC$.
4.6
0
7,766.4375
-1
7,766.4375
You have nine coins: a collection of pennies, nickels, dimes, and quarters having a total value of $1.02, with at least one coin of each type. How many dimes must you have?
1
1. **Identify the minimum number of coins and their values**: We know that there is at least one coin of each type (penny, nickel, dime, and quarter). The minimum value from one of each type is: \[ 1 \text{ cent (penny)} + 5 \text{ cents (nickel)} + 10 \text{ cents (dime)} + 25 \text{ cents (quarter)} = 41 \text{...
0.75
6,145.5625
5,463.416667
8,192
Let \( x, y \in \mathbf{R}^{+} \), and \(\frac{19}{x}+\frac{98}{y}=1\). Find the minimum value of \( x + y \).
117 + 14 \sqrt{38}
0.5
7,396.5
6,776.25
8,016.75
Calculate the product of all prime numbers between 1 and 20.
9699690
0.9375
729.625
739.2
586
Using the Horner's method (also known as Qin Jiushao's algorithm), calculate the value of the polynomial \\(f(x)=12+35x-8x^{2}+79x^{3}+6x^{4}+5x^{5}+3x^{6}\\) when \\(x=-4\\), and determine the value of \\(V_{3}\\).
-57
0.75
3,736.625
3,126.833333
5,566
An arbitrary point \( E \) inside the square \( ABCD \) with side length 1 is connected by line segments to its vertices. Points \( P, Q, F, \) and \( T \) are the points of intersection of the medians of triangles \( BCE, CDE, DAE, \) and \( ABE \) respectively. Find the area of the quadrilateral \( PQFT \).
\frac{2}{9}
0.5625
6,846.625
5,800.222222
8,192
Along the school corridor hangs a Christmas garland consisting of red and blue bulbs. Next to each red bulb, there must be a blue bulb. What is the maximum number of red bulbs that can be in this garland if there are a total of 50 bulbs?
33
0
7,112.9375
-1
7,112.9375
Simplify $2 \cos ^{2}(\ln (2009) i)+i \sin (\ln (4036081) i)$.
\frac{4036082}{4036081}
We have $2 \cos ^{2}(\ln (2009) i)+i \sin (\ln (4036081) i) =1+\cos (2 \ln (2009) i)+i \sin (\ln (4036081) i) =1+\cos (\ln (4036081) i)+i \sin (\ln (4036081) i) =1+e^{i^{2} \ln (4036081)} =1+\frac{1}{4036081} =\frac{4036082}{4036081}$ as desired.
0
8,192
-1
8,192
Find the values of $a$, $b$, and $c$ such that the equation $\sin^2 x + \sin^2 3x + \sin^2 4x + \sin^2 5x = 3$ can be reduced to an equivalent form involving $\cos ax \cos bx \cos cx = 0$ for some positive integers $a$, $b$, and $c$, and then find $a + b + c$.
12
0
8,192
-1
8,192
There are three sets of cards in red, yellow, and blue, with five cards in each set, labeled with the letters $A, B, C, D,$ and $E$. If 5 cards are drawn from these 15 cards, with the condition that all letters must be different and all three colors must be included, how many different ways are there to draw the cards?
150
0.125
7,605.3125
6,163.5
7,811.285714
How many digits are there in the base-7 representation of $956$?
4
1
3,204
3,204
-1
The diagram shows a rhombus and two sizes of regular hexagon. What is the ratio of the area of the smaller hexagon to the area of the larger hexagon?
1:4
0
8,135.125
-1
8,135.125
Among 150 schoolchildren, only boys collect stamps. 67 people collect USSR stamps, 48 people collect African stamps, and 32 people collect American stamps. 11 people collect only USSR stamps, 7 people collect only African stamps, 4 people collect only American stamps, and only Ivanov collects stamps from the USSR, Afri...
66
0.0625
7,308.6875
7,207
7,315.466667