task_type
stringclasses
4 values
problem
stringlengths
14
5.23k
solution
stringlengths
1
8.29k
problem_tokens
int64
9
1.02k
solution_tokens
int64
1
1.98k
math
A sequence begins with 3, and each subsequent term is triple the sum of all preceding terms. Determine the first term in the sequence that exceeds 15000.
36864
36
5
math
Given a cube \( ABCD-A_{1}B_{1}C_{1}D_{1} \) with edge length 2, connect \( D_{1}A \) and \( D_{1}B \). Let \( E \) be the midpoint of \( D_{1}B \), \( F \) be the midpoint of \( BC \), and \( G \) be the midpoint of \( AD_{1} \). Find the angle between the skew lines \( DG \) and \( EF \).
60^\circ
109
4
math
Given the function $f(x)=a^{2}\sin 2x+(a-2)\cos 2x$, if its graph is symmetric about the line $x=-\frac{\pi}{8}$, determine the maximum value of $f(x)$.
4\sqrt{2}
54
6
math
When the mean, median, and mode of the list 1, 2, 5, 2, 3, 2, x are arranged in increasing order, they form a non-constant arithmetic progression. Also, including x, the list remains symmetric. Find the sum of all possible real values of $x$.
6
67
1
math
In $\triangle ABC$, the sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. The following conclusions are given: 1. If $A > B > C$, then $\sin A > \sin B > \sin C$; 2. There exist $A$, $B$, and $C$ such that $\tan A\tan B\tan C < \tan A+\tan B+\tan C$; 3. If $\sin ^{2}A+\sin ^{2}B > \sin ^{2}...
1, 4
201
4
math
Given the complex number $z=1-2i$ (where $i$ is the imaginary unit), calculate the expression $z\cdot \bar{z}+z$.
6-2i
37
4
math
In the Cartesian coordinate system $xOy$, the parametric equations of curve $C$ are $\begin{cases}x=2\cos \alpha \\ y=\sin \alpha \\ \end{cases}$ (where $\alpha$ is the parameter). Establish a polar coordinate system with the origin $O$ as the pole and the positive $x$-axis as the polar axis. 1. Find the polar coordin...
\frac{4}{5}
130
7
math
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
96
4
math
The number 12320 is written on the board. Petya appended $10n + 1$ threes to it, where $n$ is a nonnegative integer. Vasya thought this was a base-4 number representing a natural number $x$, and he factored $x$ into prime factors. It turned out that there were exactly two distinct prime factors among them. For which $n...
n = 0
93
4
math
A circle of radius $r$ and a right-angled isosceles triangle are drawn such that one of the shorter sides of the triangle is a diameter of the circle. What is the shaded area? A) $\sqrt{2} r$ B) $r^{2}$ C) $2 \pi r$ D) $\frac{\pi r^{2}}{4}$ E) $(\sqrt{2}-1) \pi r^{2}$
r^2
97
3
math
In the plane, 2013 red points and 2014 blue points are marked so that no three of the marked points are collinear. One needs to draw \( k \) lines not passing through the marked points and dividing the plane into several regions. The goal is to do it in such a way that no region contains points of both colors. Find th...
2013
103
4
math
Given α, β, γ ∈ [0, 2π] and $\sin(α - β) = \frac{1}{4}$, find the maximum value of $\sin(α - γ) + \cos(β - γ)$.
\frac{\sqrt{10}}{2}
52
11
math
Given the functions $f(x)=x^{2}+2bx$ and $g(x)=|x-1|$, if for any $x_{1}$, $x_{2} \in [0,2]$, when $x_{1} < x_{2}$, we always have $f(x_{1})-f(x_{2}) < g(x_{1})-g(x_{2})$, then the minimum value of the real number $b$ is $\_\_\_\_\_\_$.
-\frac{1}{2}
108
7
math
Given a right circular cone with a base radius of \(1 \, \text{cm}\) and a slant height of \(3 \, \text{cm}\), point \(P\) is on the circumference of the base. Determine the shortest distance from the vertex \(V\) of the cone to the shortest path from \(P\) back to \(P\).
1.5
75
3
math
Given a modified Fibonacci sequence that starts with $F_1 = 2$ and $F_2 = 2$, and each subsequent term is the sum of its two predecessors, modulo 7, determine the last digit from 0 to 6 that appears in the units position of a number in this sequence.
0
64
1
math
Given that the center of the ellipse $C$ is at the origin and its foci lie on the $x$-axis. If the eccentricity of the ellipse $C$ is equal to $\frac{1}{2}$, and one of its vertices coincides with the focus of the parabola $x^{2}=8 \sqrt{3}y$, find the standard equation of the ellipse $C$.
\frac{x^{2}}{16} + \frac{y^{2}}{12} = 1
86
25
math
If $2 - \sin^{2}(x + 2y - 1) = \frac{x^{2} + y^{2} - 2(x + 1)(y - 1)}{x - y + 1}$, then the minimum value of the product $xy$ is $\qquad$ .
1/9
68
3
math
Given that in $\triangle ABC$, the sides opposite to the internal angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively, and $b = a \tan B$, with $A$ being an obtuse angle, find $A - B$.
\frac{\pi}{2}
62
7
math
Let point $O$ be the origin in a three-dimensional coordinate system, and let points $A$, $B$, and $C$ be located on the positive $x$, $y$, and $z$ axes respectively. If $OA = \sqrt[3]{50}$ and $\angle BAC = 45^\circ$, compute the area of triangle $ABC$.
25
78
2
math
The domain of the function \\(f(x)=\dfrac{1}{x}\ln (\sqrt{x^{2}-3x+2}+\sqrt{-x^{2}-3x+4})\\) is __________.
[-4,0) \cup (0,1)
48
12
math
Suppose $X$ is a random variable that takes on only nonnegative integer values, with $E[X]=1,$ $E[X^2]=2,$ and $E[X^3]=5.$ (Here $E[Y]$ denotes the expectation of the random variable $Y.$ ) Determine the smallest possible value of the probability of the event $X=0.$
\frac{1}{3}
87
7
math
Given the universal set $U={1,3,5,7,9}$, set $A={1,|a-5|,9}$, and the complement of $A$ in $U$, $∁_{U}A={5,7}$, find the value of $a$.
2, 8
64
4
math
In 2016, the fourth-grade class of Hua Sheng Education carried out extracurricular reading activities. If they read 800 characters every day, then in 7 days a week they will read ______ characters, and in 20 weeks, they will need to read ______ characters. After omitting the digits following the ten-thousands place, th...
5600, 112000, 11
87
16
math
Given that each of the triangles $\triangle QPT$, $\triangle QTS$, and $\triangle QSR$ is an isosceles right-angled triangle with $\angle QPT = \angle QTS = \angle QSR = 90^{\circ}$, find the value of $k$ if the combined area of the three triangles is 56, where $QP = PT = k$.
4
84
1
math
Given the function $f(x)=|x-a|+4x$, where $a > 0$. (1) When $a=2$, find the solution set of the inequality $f(x)\geqslant 2x+1$. (2) If $x\in(-2,+\infty)$ always satisfies $f(2x) > 7x+a^{2}-3$, find the range of values for $a$.
a\in(0,2)
96
8
math
Let the right focus of the hyperbola $\dfrac {x^{2}}{a^{2}} - \dfrac {y^{2}}{b^{2}} = 1 (a > 0, b > 0)$ be $F$. A line $l$, perpendicular to the $x$-axis and passing through point $F$, intersects the two asymptotes at points $A$ and $B$, and intersects the hyperbola in the first quadrant at point $P$. Let $O$ be the or...
2
176
1
math
What is the smallest integer $n$ , greater than one, for which the root-mean-square of the first $n$ positive integers is an integer? $\mathbf{Note.}$ The root-mean-square of $n$ numbers $a_1, a_2, \cdots, a_n$ is defined to be \[\left[\frac{a_1^2 + a_2^2 + \cdots + a_n^2}n\right]^{1/2}\]
\(\boxed{337}\)
104
9
math
The ratio of girls to boys in Mr. Green's science class is 4:3. If there are a total of 56 students in the class, how many girls and boys are there in Mr. Green's science class?
24
48
2
math
Let \( a \in \mathbf{R}_{+} \). The equation \( x^{2} - 2a x - 2a \ln x = 0 \) has a unique solution in the interval \( (0, +\infty) \). Find the value of \( a \).
\frac{1}{2}
65
7
math
In $\triangle ABC$, the angles $A$, $B$, $C$ have opposite sides $a$, $b$, $c$ respectively, with $B=\frac{\pi}{3}$, $\cos A=\frac{4}{5}$, and $b=\sqrt{3}$. (1) Find the value of $\sin C$; (2) Find the area of $\triangle ABC$.
\frac{36 + 9\sqrt{3}}{50}
84
17
math
The number $(\sqrt{5} + 2)^{1997}$ rounded to 100 digits after the decimal point is calculated to find the 100th digit after the decimal point.
0
45
1
math
Let $x$ represent the cost of one copy of the newsletter. Fourteen copies cost 14$x$ dollars and nineteen copies cost 19$x$ dollars. It is given that 14$x$ < $16.00 and 19$x$ > $21.00. Find the value of $x$.
1.11
72
4
math
Find the minimum positive integer $k$ such that there exists a function $f$ from the set $\Bbb{Z}$ of all integers to $\{1, 2, \ldots k\}$ with the property that $f(x) \neq f(y)$ whenever $|x-y| \in \{5, 7, 12\}$ .
4
89
1
math
How many positive multiples of 3 that are less than 150 have a units digit of 3?
5
23
1
math
Find the sum of all complex numbers $z$ that satisfy \[z^3 + z^2 - |z|^2 + 2z = 0.\]
-2
35
2
math
Given $3^{7} + 1$ and $3^{15} + 1$ inclusive, how many perfect cubes lie between these two values?
231
33
3
math
Find the minimum value of the distance $|AB|$ where point $A$ is the intersection of the line $y=a$ and the line $y=2x+2$, and point $B$ is the intersection of the line $y=a$ and the curve $y=x+\ln x$.
\frac{3}{2}
62
7
math
An air force squadron is holding a stunt flying performance, during which a plane takes off and completes 4 performance maneuvers after flying $0.5km$. The changes in height of the plane are shown in the table below. | Maneuver | Height Change | Notation | |----------|---------------|----------| | Maneuver 1 | Ascend ...
49L
225
3
math
Given the function $f(x)=e^{x}+ax+1$ $(a\in \mathbb{R})$. If $x=0$ is an extremum point of $f(x)$, (I) find $a$, and determine the minimum value of $f(x)$ on the interval $[-2,1]$; (II) if the inequality $kf'(x) < xe^{x}+1$ holds for any $x > 0$, where $k$ is an integer and $f'(x)$ is the derivative of $f(x)$, find...
2
130
1
math
Given an arithmetic sequence $\{a\_n\}$, the sum of its first $n$ terms, $S\_n$, satisfies $S\_3=0$ and $S\_5=-5$. The sum of the first 2016 terms of the sequence $\{ \frac{1}{a_{2n-1}a_{2n+1}} \}$ is $\_\_\_\_\_\_\_\_.$
-\frac{2016}{4031}
91
13
math
Given points P(-2,-3) and Q(5,3) in the xy-plane; point R(x,m) is such that x=2 and PR+RQ is a minimum. Find m.
\frac{3}{7}
43
7
math
Let \( a, b, c \) be the roots of \( x^3 - 9x^2 + 11x - 1 = 0 \), and let \( s = \sqrt{a} + \sqrt{b} + \sqrt{c} \). Find \( s^4 - 18s^2 - 8s \).
-37
78
3
math
Given unit vectors $\overrightarrow{a}$ and $\overrightarrow{b}$ forming an acute angle, and the magnitude $|\overrightarrow{a} - t\overrightarrow{b}|$ (where $t \in \mathbb{R}$) has a minimum value of $\frac{\sqrt{3}}{2}$, 1. Find the value of $(\overrightarrow{a} + \overrightarrow{b})(\overrightarrow{a} - 2\overright...
\frac{\sqrt{3}}{2}
163
10
math
The perimeter of a rectangle is 40 meters and its area is exactly 96 square meters. What are the possible dimensions of this rectangle?
(8, 12)
30
7
math
A fair 6-sided die is rolled. If I roll $n$, then I win $(n^3 - 2n)$ dollars if $n < 4$, and $n^3$ dollars if $n \geq 4$. What is the expected value of my winnings? Express your answer as a dollar value rounded to the nearest cent.
\$71.50
73
6
math
If the function $f(x)=\frac{{a{x^3}+(a-1)x+a-2b}}{x}$ is an even function defined on $\left(-2a+2,0\right)\cup \left(0,a\right)$, find the value of $f\left(1\right)$.
3
70
1
math
There are five volunteers, including A and B, who are assigned to serve at different positions in the China Pavilion, the UK Pavilion, the Australia Pavilion, and the Russia Pavilion at the Shanghai World Expo. Each position must be staffed by at least one volunteer. How many ways are there for A and B to each independ...
72
76
2
math
Find the repetend in the decimal representation of $\frac{5}{17}.$
294117
18
6
math
The lengths of the legs of a certain right triangle are the roots of the equation \( a x^{2} + b x + c = 0 \). Find the radius of the circle inscribed in this triangle.
-\frac{b + \sqrt{b^2 - 2ac}}{2a}
44
20
math
A gumball machine contains $9$ red, $7$ white, and $8$ blue gumballs. The least number of gumballs a person must buy to be sure of getting four gumballs of the same color is
10
51
2
math
As shown in Figure 3, in \(\triangle ABC\), \(O\) is the midpoint of side \(BC\). A line through point \(O\) intersects lines \(AB\) and \(AC\) at different points \(M\) and \(N\) respectively. If $$ \begin{array}{l} \overrightarrow{AB}=m \overrightarrow{AM}, \\ \overrightarrow{AC}=n \overrightarrow{AN}, \end{array} $$...
2
108
1
math
Given a geometric sequence $\{a_n\}$, the sum of the first $n$ terms is $S_n$, and it is known that $a_4=2a_5$, and $S_6= \frac{63}{64}$; $(1)$ Find the sum of the first $n$ terms of the sequence $\{a_n\}$, $S_n$; $(2)$ Let $b_n= \frac{2^n a_n}{n^2+n}$, find the sum of the first $n$ terms of the sequence $\{b_n\}$, $...
\frac{n}{n+1}
130
8
math
Given vectors $a=\left( \sin\left( \alpha+\frac{\pi}{6} \right),3 \right)$ and $b=(1,4\cos \alpha)$, where $\alpha\in(0,\pi)$. (1) If $a\perp b$, find the value of $\tan \alpha$; (2) If $a\parallel b$, find the value of $\alpha$.
\frac{\pi}{6}
90
7
math
Given the complex number $z=\frac{2i}{3+i}$, determine the conjugate complex number of $z$.
\frac{1}{5}-\frac{3}{5}i
26
15
math
Five numbers, \( c_1, c_2, c_3, c_4, c_5 \), are drawn randomly and without replacement from the set of even numbers between 1 and 100, inclusive. Let \( p \) be the probability that, after a suitable rotation, a brick of dimensions \( c_1 \times c_2 \) can be enclosed in a box of dimensions \( c_3 \times c_4 \), with ...
3
171
1
math
In a larger square grid of 10 x 10 units, a shaded region is constructed using the following points of the large square grid: lower left corner, midpoint of right edge, midpoint of top edge, and center of the square. What is the ratio of the area of the shaded region to the area of the large square?
\frac{1}{8}
69
7
math
Find the number of permutations $x_1, x_2, x_3, x_4, x_5$ of numbers $1, 2, 3, 4, 5$ such that the sum of five products $$ x_1x_2x_3 + x_2x_3x_4 + x_3x_4x_5 + x_4x_5x_1 + x_5x_1x_2 $$ is divisible by $3$ .
80
115
2
math
What is the average speed for the entire race where the triathlete swims 5 km at 3 kilometers per hour, bikes 30 km at 25 kilometers per hour, and runs 15 km at 8 kilometers per hour?
10.54
50
5
math
Given the function $f\left( x \right)=\frac{{{x}^{2}}}{1+{{x}^{2}}}$. (1) Find the values of $f\left( 2 \right)+f\left( \frac{1}{2} \right),f\left( 3 \right)+f\left( \frac{1}{3} \right),f\left( 4 \right)+f\left( \frac{1}{4} \right)$ and conjecture a general conclusion (proof is not required). (2) Evaluate: $2f\left(2...
4032
266
4
math
An Ultraman is fighting a group of monsters. It is known that Ultraman has one head and two legs. Initially, each monster has two heads and five legs. During the battle, some monsters split, with each splitting monster creating two new monsters, each with one head and six legs (they cannot split again). At a certain mo...
13
93
2
math
There are 5 female students and 2 male students in a class. Find the number of different distribution schemes in which they can be divided into two groups, with each group having both female and male students.
60
42
2
math
Solve for $y$ in terms of $b$, where $b \neq 0$, given the determinant: \[ \begin{vmatrix} y + b & -y & y \\ -y & y + b & -y \\ y & -y & y + b \end{vmatrix} = 0. \]
y = -\frac{b}{3}
72
10
math
Professor Fernando's tree grows according to the following rule: - In the first week, the tree starts to grow with only one branch; - After growing for two weeks, this branch produces a new branch every week; - Each new branch continues to grow and, after growing for two weeks, produces a new branch every week. The f...
233
152
3
math
Let $\triangle XYZ$ be a right triangle with $Y$ as the right angle. A circle with diameter $YZ$ intersects side $XZ$ at point $W$. If $XW = 3$ and $YW = 9$, find the length of segment $ZW$.
27
59
2
math
Consider an unusual biased coin, with probability $p$ of landing heads, probability $q \leq p$ of landing tails, and probability \frac{1}{6}$ of landing on its side (i.e. on neither face). It is known that if this coin is flipped twice, the likelihood that both flips will have the same result is \frac{1}{2}$. Find $p$.
\frac{2}{3}
83
7
math
A schematic diagram of a computer device is shown. \( J_1 \) and \( J_2 \) represent data inputs, and \( C \) is the output for the calculation result. The calculation process involves inputting natural numbers \( m \) and \( n \) into \( J_1 \) and \( J_2 \) respectively, after which a natural number \( k \) is output...
2^{2001} + 16
297
11
math
Given the one-variable quadratic equation in $x$, $(k+2)x^{2}-2x-1=0$, determine the range of real number $k$ for which the equation has real roots.
k\geqslant -3 \text{ and } k\neq -2
42
19
math
Let \( D, E, \) and \( F \) be points on a circle of radius \( 25 \). If \( \angle EFD = 120^\circ \), what is the length of the circumference of the minor arc \( DE \)? Express your answer in terms of \( \pi \).
\frac{50\pi}{3}
67
10
math
Two distinct positive integers \( a \) and \( b \) are factors of 48. If \( a \cdot b \) is not a factor of 48, what is the smallest possible value of \( a \cdot b \)?
18
51
2
math
Let $\binom{n}{j}=\frac{n!}{j!(n-j)!}$. Evaluate the value of $\sum_{k=1}^{49}(-1)^{k}\binom{99}{2k}$.
-2^{49}
51
6
math
The force required to loosen bolts varies inversely with the length of the wrench handle used. Using a wrench with a handle length of 10 inches requires 300 pounds of force to loosen Bolt A. To loosen Bolt B, which is tighter and requires 400 pounds of force with a 10-inch handle, how many pounds of force will be neede...
200
85
3
math
What are the first three digits to the right of the decimal point in the decimal representation of $\left(10^{2003}+1\right)^{11/8}$?
375
41
3
math
Given the sequence {a<sub>n</sub>} with the sum of its first n terms S<sub>n</sub> = n<sup>2</sup> - 2n + 2, find a<sub>1</sub> and a<sub>n</sub>.
1
60
1
math
Given the ellipse $\dfrac{x^2}{m^2} + y^2 = 1$ ($m > 1$) and the hyperbola $\dfrac{x^2}{n^2} - y^2 = 1$ ($n > 0$), both sharing a common focus $F_1$. Find the area of the triangle $\triangle F_1 P F_2$.
1
86
1
math
What amount can a worker, who is a tax resident, expect after paying personal income tax if they are credited with 45000 for their work?
39150
33
5
math
Given a rectangular prism with edge dimensions 4, 2, and 3, calculate how many unordered pairs of edges determine a plane.
42
28
2
math
A real number $x$ is randomly selected from the interval $[-π,π]$. The probability of the event "$\sin x \geq \frac{1}{2}$" occurring is $\_\_\_\_\_\_\_.$
\frac{1}{3}
50
7
math
Let $x$ and $y$ be positive integers such that $xy - 10x + 3y = 670$. What is the smallest possible value of $|x - y|$?
16
44
2
math
Given an ellipse with foci on the $x$-axis and a minor axis length of 4, the eccentricity is $\frac{\sqrt{5}}{5}$. $(1)$ Find the standard equation of the ellipse; $(2)$ If line $l$ passes through the left focus of the ellipse and intersects the ellipse at points $M$ and $N$, with $\left| MN \right|=\dfrac{16}{9}\...
y = x + 1 \quad \text{or} \quad y = -x - 1
109
22
math
Given \( x_{i} \in \{-1,1\}, i=1,2,\cdots,2021 \), and \( x_{1}+x_{2}+\cdots+x_{k} \geq 0 \) for \( k=1,2,\cdots,2020 \), with \( x_{1}+x_{2}+\cdots+x_{2021}=-1 \). How many ordered arrays \( (x_{1}, x_{2}, \cdots, x_{2021}) \) are there?
\frac{1}{1011} \binom{2020}{1010}
127
24
math
Compute the value of $\cos 80^{\circ}\cos 20^{\circ}+\sin 80^{\circ}\sin 20^{\circ}$.
\dfrac{1}{2}
39
7
math
The school organized a summer camp during the summer vacation. The school contacted two travel agencies, both of which quoted a price of $200 per person. After negotiation, Travel Agency A's discount condition was: a 25% discount for all teachers and students; Travel Agency B's discount condition was: the fee for one t...
x > 16
146
5
math
There are 8 different books, including 3 math books, 3 foreign language books, and 2 literature books. If these books are arranged in a row on a bookshelf, in how many ways can the arrangement be made such that all math books are together and all foreign language books are also together?
864
63
3
math
Given points P<sub>1</sub>(x<sub>1</sub>, y<sub>1</sub>) and P<sub>2</sub>(x<sub>2</sub>, y<sub>2</sub>) on a unit circle with center O, and ∠P<sub>1</sub>OP<sub>2</sub>=θ (θ is an obtuse angle). If sin(θ + $\frac{π}{4}$) = $\frac{3}{5}$, find the value of x<sub>1</sub>x<sub>2</sub> + y<sub>1</sub>y<sub>2</sub>.
-$\frac{\sqrt{2}}{10}$
144
12
math
The area of triangle \( ABC \) is 1. On the rays \( AB \), \( BC \), and \( CA \), points \( B' \), \( C' \), and \( A' \) are marked respectively, such that: \[ BB' = AB, \quad CC' = 2BC, \quad AA' = 3CA \] Calculate the area of triangle \( A'B'C' \).
18
89
2
math
In the Cartesian coordinate system $xOy$, the parametric equation of curve $C$ is $\begin{cases}x=2\cos \alpha \\ y=2+2\sin \alpha\end{cases}$ (where $\alpha$ is the parameter), and the parametric equation of line $l$ is $\begin{cases}x= \sqrt{3}- \dfrac{ \sqrt{3}}{2}t \\ y=3+ \dfrac{1}{2}t\end{cases}$ (where $t$ is th...
2 \sqrt{3}
258
6
math
The towns in one country are connected with bidirectional airlines, which are paid in at least one of the two directions. In a trip from town A to town B there are exactly 22 routes that are free. Find the least possible number of towns in the country.
7
56
1
math
Given $f(x)=4x^{5}+3x^{4}+2x^{3}-x^{2}-x-\frac{1}{2}$, use Horner's method to find $f(-2)$.
-\frac{197}{2}
48
9
math
Find the value of $\frac{2468_{7}}{123_{5}} - 3214_{6} + 7891_{8}$ and express your answer in base 10.
3464
49
4
math
Given that $1,3,5,7,\ldots,\beta$ and $1,6,11,16,\ldots,\beta+1$ are two finite sequences of positive integers, determine $\gamma$, the number of positive integers common to both sequences.
6
57
1
math
There are $24$ different pencils, $4$ different colors, and $6$ pencils of each color. They were given to $6$ children in such a way that each got $4$ pencils. What is the least number of children that you can randomly choose so that you can guarantee that you have pencils of all colors. P.S. for 10 grade gi...
5
117
3
math
What is the modular inverse of $13$, modulo $2000$? Express your answer as an integer from $0$ to $1999$, inclusive.
1077
37
4
math
Point \( M \) lies on the edge \( AB \) of cube \( ABCD A_1 B_1 C_1 D_1 \). A rectangle \( MNLK \) is inscribed in square \( ABCD \) such that one of its vertices is point \( M \) and the other three vertices are located on different sides of the square base. Rectangle \( M_1 N_1 L_1 K_1 \) is the orthogonal projection...
1:2
187
3
math
The equations of $L_1$ and $L_2$ are $y=mx$ and $y=nx$, respectively. Suppose $L_1$ makes twice as large of an angle with the horizontal (measured counterclockwise from the positive x-axis ) as does $L_2$, and that $L_1$ has 4 times the slope of $L_2$. If $L_1$ is not horizontal, then $mn$ is
2
98
1
math
A bike travels $\dfrac{b}{4}$ feet every $t$ seconds. There are $3$ feet in a yard. How many yards does the bike travel in $4$ minutes? A) $\frac{15b}{t}$ B) $\frac{20b}{t}$ C) $\frac{25b}{t}$ D) $\frac{30b}{t}$
\frac{20b}{t}
88
9
math
Let $\omega$ be a nonreal root of the equation $z^4 = 1$. Let $b_1, b_2, \dots, b_n$ be real numbers such that \[ \frac{1}{b_1 + \omega} + \frac{1}{b_2 + \omega} + \dots + \frac{1}{b_n + \omega} = 3 + 4i. \] Compute \[ \frac{2b_1 - 1}{b_1^2 - b_1 + 1} + \frac{2b_2 - 1}{b_2^2 - b_2 + 1} + \dots + \frac{2b_n - 1}{b_n^2 -...
6
174
1
math
Positive real numbers \( x, y, z \) satisfy \[ \left\{ \begin{array}{l} \frac{2}{5} \leqslant z \leqslant \min \{x, y\}, \\ xz \geqslant \frac{4}{15}, \\ yz \geqslant \frac{1}{5}. \end{array} \right. \] Find the maximum value of \( \frac{1}{x} + \frac{2}{y} + \frac{3}{z} \).
13
123
2
math
Determine the largest value of \(n\) such that \(6x^2 + nx + 48\) can be factored into the product of two linear factors with integer coefficients.
n = 289
38
6
math
Calculate:<br/>$(1)15+(-22)$;<br/>$(2)(-13)+(-8)$;<br/>$(3)(-0.9)+1.5$;<br/>$(4)\frac{1}{2}+(-\frac{2}{3})$.
-\frac{1}{6}
64
7
math
The lateral surface of a cylinder unfolds into a rectangle with sides of length $6\pi$ and $4\pi$. Then, the surface area of the cylinder is ______.
24\pi^2 + 8\pi
36
11