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There are two distinguishable flagpoles, and there are $17$ flags, of which $11$ are identical red flags, and $6$ are identical white flags. Determine the number of distinguishable arrangements using all of the flags such that each flagpole has at least one flag and no two white flags on either pole are adjacent. Compute the remainder when this number is divided by $1000$.
|
164
|
Without using a calculator, find the largest prime factor of $15^4+2\times15^2+1-14^4$.
|
211
|
If $\mathbf{a},$ $\mathbf{b},$ and $\mathbf{c}$ are vectors such that $\|\mathbf{a}\| = \|\mathbf{b}\| = 1,$ $\|\mathbf{a} + \mathbf{b}\| = \sqrt{3},$ and
\[\mathbf{c} - \mathbf{a} - 2 \mathbf{b} = 3 (\mathbf{a} \times \mathbf{b}),\]then find $\mathbf{b} \cdot \mathbf{c}.$
|
\frac{5}{2}
|
Let \(a_{1}, a_{2}, \cdots, a_{n}\) be an increasing sequence of positive integers. For a positive integer \(m\), define
\[b_{m}=\min \left\{n \mid a_{n} \geq m\right\} (m=1,2, \cdots),\]
that is, \(b_{m}\) is the smallest index \(n\) such that \(a_{n} \geq m\). Given \(a_{20}=2019\), find the maximum value of \(S=\sum_{i=1}^{20} a_{i}+\sum_{i=1}^{2019} b_{i}\).
|
42399
|
Let function $G(n)$ denote the number of solutions to the equation $\cos x = \sin nx$ on the interval $[0, 2\pi]$. For each integer $n$ greater than 2, what is the sum $\sum_{n=3}^{100} G(n)$?
|
10094
|
Let $x$ and $y$ be real numbers such that $2(x^2 + y^2) = x + y.$ Find the maximum value of $x - y.$
|
\frac{1}{2}
|
An equilateral triangle and a square have the same perimeter of 12 inches. What is the ratio of the side length of the triangle to the side length of the square? Express your answer as a common fraction.
|
\frac{4}{3}
|
The slope angle of the tangent line to the curve y=\frac{1}{3}x^{3} at x=1 is what value?
|
\frac{\pi}{4}
|
A basketball player made the following number of successful free throws in 10 successive games: 8, 17, 15, 22, 14, 12, 24, 10, 20, and 16. He attempted 10, 20, 18, 25, 16, 15, 27, 12, 22, and 19 free throws in those respective games. Calculate both the median number of successful free throws and the player's best free-throw shooting percentage game.
|
90.91\%
|
A famous theorem states that given any five points in the plane, with no three on the same line, there is a unique conic section (ellipse, hyperbola, or parabola) which passes through all five points. The conic section passing through the five points \[(-\tfrac32, 1), \; (0,0), \;(0,2),\; (3,0),\; (3,2).\]is an ellipse whose axes are parallel to the coordinate axes. Find the length of its minor axis.
|
\frac{4\sqrt3}{3}
|
Compute the sum \[\lfloor \sqrt{1} \rfloor + \lfloor \sqrt{2} \rfloor + \lfloor \sqrt{3} \rfloor + \cdots + \lfloor \sqrt{25} \rfloor.\]
|
75
|
Let $x,$ $y,$ and $z$ be nonnegative real numbers such that $x + y + z = 5.$ Find the maximum value of
\[\sqrt{2x + 1} + \sqrt{2y + 1} + \sqrt{2z + 1}.\]
|
\sqrt{39}
|
Given a plane $\alpha$ and two non-coincident straight lines $m$ and $n$, consider the following four propositions:
(1) If $m \parallel \alpha$ and $n \subseteq \alpha$, then $m \parallel n$.
(2) If $m \parallel \alpha$ and $n \parallel \alpha$, then $m \parallel n$.
(3) If $m \parallel n$ and $n \subseteq \alpha$, then $m \parallel \alpha$.
(4) If $m \parallel n$ and $m \parallel \alpha$, then $n \parallel \alpha$ or $n \subseteq \alpha$.
Identify which of the above propositions are correct (write the number).
|
(4)
|
Given a triangular pyramid where two of the three lateral faces are isosceles right triangles and the third face is an equilateral triangle with a side length of 1, calculate the volume of this triangular pyramid.
|
\frac{\sqrt{3}}{12}
|
Given that $x$ is a multiple of $2520$, what is the greatest common divisor of $g(x) = (4x+5)(5x+2)(11x+8)(3x+7)$ and $x$?
|
280
|
The bases \( AB \) and \( CD \) of the trapezoid \( ABCD \) are equal to 65 and 31 respectively, and its lateral sides are mutually perpendicular. Find the dot product of the vectors \( \overrightarrow{AC} \) and \( \overrightarrow{BD} \).
|
-2015
|
A paper equilateral triangle $ABC$ has side length $12$. The paper triangle is folded so that vertex $A$ touches a point on side $\overline{BC}$ a distance $9$ from point $B$. The length of the line segment along which the triangle is folded can be written as $\frac{m\sqrt{p}}{n}$, where $m$, $n$, and $p$ are positive integers, $m$ and $n$ are relatively prime, and $p$ is not divisible by the square of any prime. Find $m+n+p$.
[asy] import cse5; size(12cm); pen tpen = defaultpen + 1.337; real a = 39/5.0; real b = 39/7.0; pair B = MP("B", (0,0), dir(200)); pair A = MP("A", (9,0), dir(-80)); pair C = MP("C", (12,0), dir(-20)); pair K = (6,10.392); pair M = (a*B+(12-a)*K) / 12; pair N = (b*C+(12-b)*K) / 12; draw(B--M--N--C--cycle, tpen); draw(M--A--N--cycle); fill(M--A--N--cycle, mediumgrey); pair shift = (-20.13, 0); pair B1 = MP("B", B+shift, dir(200)); pair A1 = MP("A", K+shift, dir(90)); pair C1 = MP("C", C+shift, dir(-20)); draw(A1--B1--C1--cycle, tpen);[/asy]
|
113
|
Marsha now has two numbers, $a$ and $b$. When she divides $a$ by $60$ she gets a remainder of $58$. When she divides $b$ by $90$ she gets a remainder of $84$. What remainder does she get when she divides $a+b$ by $30$?
|
22
|
Susan has 21 cats and Bob has 3 cats. If Susan gives Robert 4 of her cats, how many more cats does Susan have than Bob?
|
After giving away four of her cats, Susan has 21 - 4 = <<21-4=17>>17.
Susan has 17 - 3 = <<17-3=14>>14 more cats than Bob
#### 14
|
If
\begin{align*}
a + b + c &= 1, \\
a^2 + b^2 + c^2 &= 2, \\
a^3 + b^3 + c^3 &= 3,
\end{align*}find $a^4 + b^4 + c^4.$
|
\frac{25}{6}
|
Jim has 2 rows of 4 trees to start. When he turns 10 he decides to plant a new row of trees every year on his birthday. On his 15th birthday after he doubles the number of trees he has. How many trees does he have?
|
He started with 2*4=<<2*4=8>>8 trees
He plants trees for 15-10=<<15-10=5>>5 years
So he planted 5*4=<<5*4=20>>20 trees
So he had 20+8=<<20+8=28>>28 trees
After doubling them he had 28*2=<<28*2=56>>56 trees
#### 56
|
What is the sum of all values of $z$ such that $z^2=12z-7$?
|
12
|
Let $a,$ $b,$ $c$ be the roots of the cubic $x^3 + 3x^2 + 5x + 7 = 0.$ Given that $P(x)$ is a cubic polynomial such that $P(a) = b + c,$ $P(b) = a + c,$ $P(c) = a + b,$ and $P(a + b + c) = -16,$ find $P(x).$
|
2x^3 + 6x^2 + 9x + 11
|
Let $$Q(x) = \left(\frac{x^{24} - 1}{x - 1}\right)^2 - x^{23}$$ and this polynomial has complex zeros in the form $z_k = r_k[\cos(2\pi\alpha_k) + i\sin(2\pi\alpha_k)]$, for $k = 1, 2, ..., 46$, where $0 < \alpha_1 \le \alpha_2 \le \ldots \le \alpha_{46} < 1$ and $r_k > 0$. Find $\alpha_1 + \alpha_2 + \alpha_3 + \alpha_4 + \alpha_5.$
|
\frac{121}{575}
|
Elmer the emu takes $44$ equal strides to walk between consecutive telephone poles on a rural road. Oscar the ostrich can cover the same distance in $12$ equal leaps. The telephone poles are evenly spaced, and the $41$st pole along this road is exactly one mile ($5280$ feet) from the first pole. How much longer, in feet, is Oscar's leap than Elmer's stride?
|
8
|
Two machine tools, A and B, produce the same product. The products are divided into first-class and second-class according to quality. In order to compare the quality of the products produced by the two machine tools, each machine tool produced 200 products. The quality of the products is as follows:<br/>
| | First-class | Second-class | Total |
|----------|-------------|--------------|-------|
| Machine A | 150 | 50 | 200 |
| Machine B | 120 | 80 | 200 |
| Total | 270 | 130 | 400 |
$(1)$ What are the frequencies of first-class products produced by Machine A and Machine B, respectively?<br/>
$(2)$ Can we be $99\%$ confident that there is a difference in the quality of the products produced by Machine A and Machine B?<br/>
Given: $K^{2}=\frac{n(ad-bc)^{2}}{(a+b)(c+d)(a+c)(b+d)}$.<br/>
| $P(K^{2}\geqslant k)$ | 0.050 | 0.010 | 0.001 |
|-----------------------|-------|-------|-------|
| $k$ | 3.841 | 6.635 | 10.828 |
|
99\%
|
Xiao Hua plays a certain game where each round can be played several times freely. Each score in a round is one of the numbers $8$, $a$ (a natural number), or $0$. The total score for a round is the sum of all individual scores in that round. Xiao Hua has achieved the following total scores in some rounds: $103, 104, 105, 106, 107, 108, 109, 110$. It is also known that he cannot achieve a total score of $83$. What is the value of $a$?
|
13
|
Two cars travel along a circular track $n$ miles long, starting at the same point. One car travels $25$ miles along the track in some direction. The other car travels $3$ miles along the track in some direction. Then the two cars are once again at the same point along the track. If $n$ is a positive integer, find the sum of all possible values of $n.$
|
89
|
If the integer solutions to the system of inequalities
\[
\begin{cases}
9x - a \geq 0, \\
8x - b < 0
\end{cases}
\]
are only 1, 2, and 3, how many ordered pairs \((a, b)\) of integers satisfy this system?
|
72
|
If \( a, b, c \) are real numbers such that \( |a-b|=1 \), \( |b-c|=1 \), \( |c-a|=2 \) and \( abc=60 \), calculate the value of \( \frac{a}{bc} + \frac{b}{ca} + \frac{c}{ab} - \frac{1}{a} - \frac{1}{b} - \frac{1}{c} \).
|
\frac{1}{10}
|
Seven cards numbered $1$ through $7$ are to be lined up in a row. Find the number of arrangements of these seven cards where one of the cards can be removed leaving the remaining six cards in either ascending or descending order.
|
74
|
A wire has a length of 6 meters and has 5 nodes that divide the wire into 6 equal parts. If a node is randomly selected to cut the wire, what is the probability that both resulting pieces will have lengths not less than 2 meters?
|
\frac{3}{5}
|
What is the volume in cubic inches of a right, rectangular prism with side, front and bottom faces having an area 15 square inches, 10 square inches and 6 square inches, respectively?
|
30
|
Hannah's AdBlock blocks all but 20% of ads, and 20% of the ads it doesn't block are actually interesting. What percentage of ads aren't interested and don't get blocked?
|
First find the percentage of ads that aren't interesting: 100% - 20% = 80%
Then multiply that percentage by the percentage of ads that don't get blocked to find the percentage of ads that meet both criteria: 80% * 20% = 16%
#### 16
|
Given that Jessica uses 150 grams of lemon juice and 100 grams of sugar, and there are 30 calories in 100 grams of lemon juice and 386 calories in 100 grams of sugar, and water contains no calories, compute the total number of calories in 300 grams of her lemonade.
|
152.1
|
Given the function $f(x)=2\sqrt{3}\sin x\cos x-\cos (\pi +2x)$.
(1) Find the interval(s) where $f(x)$ is monotonically increasing.
(2) In $\Delta ABC$, the sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. If $f(C)=1,c=\sqrt{3},a+b=2\sqrt{3}$, find the area of $\Delta ABC$.
|
\frac{3\sqrt{3}}{4}
|
In the complex plane, let the vertices \( A \) and \( B \) of triangle \( \triangle AOB \) correspond to the complex numbers \( \alpha \) and \( \beta \), respectively, and satisfy the conditions: \( \beta = (1 + i)\alpha \) and \( |\alpha - 2| = 1 \). \( O \) is the origin. Find the maximum value of the area \( S \) of the triangle \( \triangle OAB \).
|
9/2
|
Given a right triangular prism $ABC-A_{1}B_{1}C_{1}$, where $\angle BAC=90^{\circ}$, the area of the side face $BCC_{1}B_{1}$ is $16$. Find the minimum value of the radius of the circumscribed sphere of the right triangular prism $ABC-A_{1}B_{1}C_{1}$.
|
2 \sqrt {2}
|
In an isosceles triangle \(ABC\), the base \(AC\) is equal to 1, and the angle \(\angle ABC\) is \(2 \arctan \frac{1}{2}\). Point \(D\) lies on the side \(BC\) such that the area of triangle \(ABC\) is four times the area of triangle \(ADC\). Find the distance from point \(D\) to the line \(AB\) and the radius of the circle circumscribed around triangle \(ADC\).
|
\frac{\sqrt{265}}{32}
|
Let $x$ be the least real number greater than $1$ such that $\sin(x) = \sin(x^2)$, where the arguments are in degrees. What is $x$ rounded up to the closest integer?
|
13
|
The number obtained from the last two nonzero digits of $90!$ is equal to $n$. What is $n$?
|
12
|
In circle $\omega$, two perpendicular chords intersect at a point $P$. The two chords have midpoints $M_{1}$ and $M_{2}$ respectively, such that $P M_{1}=15$ and $P M_{2}=20$. Line $M_{1} M_{2}$ intersects $\omega$ at points $A$ and $B$, with $M_{1}$ between $A$ and $M_{2}$. Compute the largest possible value of $B M_{2}-A M_{1}$.
|
7
|
Given the function $f(x)=e^{x}-mx^{3}$ ($m$ is a nonzero constant).
$(1)$ If the function $f(x)$ is increasing on $(0,+\infty)$, find the range of real numbers for $m$.
$(2)$ If $f_{n+1}(x)$ ($n\in \mathbb{N}$) represents the derivative of $f_{n}(x)$, where $f_{0}(x)=f(x)$, and when $m=1$, let $g_{n}(x)=f_{2}(x)+f_{3}(x)+\cdots +f_{n}(x)$ ($n\geqslant 2, n\in \mathbb{N}$). If the minimum value of $y=g_{n}(x)$ is always greater than zero, find the minimum value of $n$.
|
n = 8
|
Let $h(x) = \sqrt[3]{\frac{2x+5}{5}}$. For what value of $x$ will $h(3x) = 3(h(x))$? Express your answer in simplest form.
|
-\frac{65}{24}
|
Two tigers, Alice and Betty, run in the same direction around a circular track with a circumference of 400 meters. Alice runs at a speed of \(10 \, \text{m/s}\) and Betty runs at \(15 \, \text{m/s}\). Betty gives Alice a 40 meter head start before they both start running. After 15 minutes, how many times will they have passed each other?
(a) 9
(b) 10
(c) 11
(d) 12
|
11
|
Five friends did gardening for their local community and earned $15, $22, $28, $35, and $50 respectively. They decide to share their total earnings equally. How much money must the friend who earned $50 contribute to the pool?
A) $10
B) $15
C) $20
D) $25
E) $35
|
20
|
Find the arithmetic mean of the reciprocals of the first three prime numbers.
|
\frac{31}{90}
|
Given a real number $x,$ let $\lfloor x \rfloor$ denote the greatest integer less than or equal to $x.$ For a certain integer $k,$ there are exactly $70$ positive integers $n_{1}, n_{2}, \ldots, n_{70}$ such that $k=\lfloor\sqrt[3]{n_{1}}\rfloor = \lfloor\sqrt[3]{n_{2}}\rfloor = \cdots = \lfloor\sqrt[3]{n_{70}}\rfloor$ and $k$ divides $n_{i}$ for all $i$ such that $1 \leq i \leq 70.$
Find the maximum value of $\frac{n_{i}}{k}$ for $1\leq i \leq 70.$
|
553
|
The number
\[e^{7\pi i/60} + e^{17\pi i/60} + e^{27 \pi i/60} + e^{37\pi i /60} + e^{47 \pi i /60}\]is expressed in the form $r e^{i \theta}$, where $0 \le \theta < 2\pi$. Find $\theta$.
|
\dfrac{9\pi}{20}
|
Given Aniyah has a $5 \times 7$ index card and if she shortens the length of one side of this card by $2$ inches, the card would have an area of $21$ square inches, determine the area of the card in square inches if she shortens the length of the other side by $2$ inches.
|
25
|
A circle is inscribed in a right triangle. The point of tangency divides the hypotenuse into two segments measuring 6 cm and 7 cm. Calculate the area of the triangle.
|
42
|
Given that $8!=40320$, what is the value of $8!\div3!$?
|
6720
|
In the trapezoid \(ABCD\), the base \(AB\) is three times longer than the base \(CD\). On the base \(CD\), point \(M\) is taken such that \(MC = 2MD\). \(N\) is the intersection point of lines \(BM\) and \(AC\). Find the ratio of the area of triangle \(MNC\) to the area of the entire trapezoid.
|
\frac{1}{33}
|
Find the sum: $1+2+3+4+\dots +48+49$
|
1225
|
Let $N$ be the greatest integer multiple of 8, no two of whose digits are the same. What is the remainder when $N$ is divided by 1000?
|
120
|
Lucy starts by writing $s$ integer-valued $2022$-tuples on a blackboard. After doing that, she can take any two (not necessarily distinct) tuples $\mathbf{v}=(v_1,\ldots,v_{2022})$ and $\mathbf{w}=(w_1,\ldots,w_{2022})$ that she has already written, and apply one of the following operations to obtain a new tuple:
\begin{align*}
\mathbf{v}+\mathbf{w}&=(v_1+w_1,\ldots,v_{2022}+w_{2022}) \\
\mathbf{v} \lor \mathbf{w}&=(\max(v_1,w_1),\ldots,\max(v_{2022},w_{2022}))
\end{align*}
and then write this tuple on the blackboard.
It turns out that, in this way, Lucy can write any integer-valued $2022$-tuple on the blackboard after finitely many steps. What is the smallest possible number $s$ of tuples that she initially wrote?
|
3
|
Find the focal length of the hyperbola that shares the same asymptotes with the hyperbola $\frac{x^{2}}{9} - \frac{y^{2}}{16} = 1$ and passes through the point $A(-3, 3\sqrt{2})$.
|
\frac{5\sqrt{2}}{2}
|
A list of five positive integers has a median of 4 and a mean of 15. What is the maximum possible value of the list's largest element?
|
65
|
A plane parallel to the base of a cone divides the height of the cone into two equal segments. What is the ratio of the lateral surface areas of the two parts of the cone?
|
\frac{1}{3}
|
A factory must filter its emissions before discharging them. The relationship between the concentration of pollutants $p$ (in milligrams per liter) and the filtration time $t$ (in hours) during the filtration process is given by the equation $p(t) = p_0e^{-kt}$. Here, $e$ is the base of the natural logarithm, and $p_0$ is the initial pollutant concentration. After filtering for one hour, it is observed that the pollutant concentration has decreased by $\frac{1}{5}$.
(Ⅰ) Determine the function $p(t)$.
(Ⅱ) To ensure that the pollutant concentration does not exceed $\frac{1}{1000}$ of the initial value, for how many additional hours must the filtration process be continued? (Given that $\lg 2 \approx 0.3$)
|
30
|
Three friends have a total of 6 identical pencils, and each one has at least one pencil. In how many ways can this happen?
|
10
|
Given sets A = {-2, 1, 2} and B = {-1, 1, 3}, calculate the probability that a line represented by the equation ax - y + b = 0 will pass through the fourth quadrant.
|
\frac{5}{9}
|
How many distinct arrangements of the letters in the word "balloon" are there?
|
1260
|
How many Pythagorean triangles are there in which one of the legs is equal to 2013? (A Pythagorean triangle is a right triangle with integer sides. Identical triangles count as one.).
|
13
|
If there are exactly $3$ integer solutions for the inequality system about $x$: $\left\{\begin{array}{c}6x-5≥m\\ \frac{x}{2}-\frac{x-1}{3}<1\end{array}\right.$, and the solution to the equation about $y$: $\frac{y-2}{3}=\frac{m-2}{3}+1$ is a non-negative number, find the sum of all integers $m$ that satisfy the conditions.
|
-5
|
Point A is the intersection of the unit circle and the positive half of the x-axis, and point B is in the second quadrant. Let θ be the angle formed by the rays OA and OB. Given sin(θ) = 4/5, calculate the value of sin(π + θ) + 2sin(π/2 - θ) divided by 2tan(π - θ).
|
-\frac{3}{4}
|
How many ways are there to label the faces of a regular octahedron with the integers 18, using each exactly once, so that any two faces that share an edge have numbers that are relatively prime? Physically realizable rotations are considered indistinguishable, but physically unrealizable reflections are considered different.
|
12
|
For positive integers $x$, let $g(x)$ be the number of blocks of consecutive 1's in the binary expansion of $x$. For example, $g(19)=2$ because $19=10011_{2}$ has a block of one 1 at the beginning and a block of two 1's at the end, and $g(7)=1$ because $7=111_{2}$ only has a single block of three 1's. Compute $g(1)+g(2)+g(3)+\cdots+g(256)$.
|
577
|
Find the sum of the roots of $\tan^2 x - 8\tan x + \sqrt{2} = 0$ that are between $x=0$ and $x=2\pi$ radians.
|
4\pi
|
Evaluate
\[\begin{vmatrix} \cos \alpha \cos \beta & \cos \alpha \sin \beta & -\sin \alpha \\ -\sin \beta & \cos \beta & 0 \\ \sin \alpha \cos \beta & \sin \alpha \sin \beta & \cos \alpha \end{vmatrix}.\]
|
1
|
In an isosceles trapezoid with bases \(a = 21\), \(b = 9\) and height \(h = 8\), find the radius of the circumscribed circle.
|
\frac{85}{8}
|
The denominator of a geometric progression \( b_{n} \) is \( q \), and for some natural \( n \geq 2 \),
$$
\log_{4} b_{2}+\log_{4} b_{3}+\ldots+\log_{4} b_{n}=4 \cdot \log_{4} b_{1}
$$
Find the smallest possible value of \( \log_{q} b_{1}^{2} \), given that it is an integer. For which \( n \) is this value achieved?
|
-30
|
Compute the value of $1^{25}+2^{24}+3^{23}+\ldots+24^{2}+25^{1}$. If your answer is $A$ and the correct answer is $C$, then your score on this problem will be $\left\lfloor 25 \mathrm{~min}\left(\left(\frac{A}{C}\right)^{2},\left(\frac{C}{A}\right)^{2}\right)\right\rfloor$.
|
66071772829247409
|
An octahedron consists of two square-based pyramids glued together along their square bases to form a polyhedron with eight faces. Imagine an ant that begins at the top vertex and walks to one of the four adjacent vertices that he randomly selects and calls vertex A. From vertex A, he will then walk to one of the four adjacent vertices that he randomly selects and calls vertex B. What is the probability that vertex B will be the bottom vertex? Express your answer as a common fraction.
[asy]
draw((-10,0)--(10,0)--(3,-15)--cycle);
draw((-10,0)--(10,0)--(3,15)--cycle);
draw((10,0)--(17,7)--(3,-15)--(17,7)--(3,15));
draw((-3,7)--(3,15)--(-3,7)--(17,7)--(-3,7)--(-10,0)--(-3,7)--(3,-15),dashed);
[/asy]
|
\frac{1}{4}
|
Ellie has found an old bicycle in a field and thinks it just needs some oil to work well again. She needs 10ml of oil to fix each wheel and will need another 5ml of oil to fix the rest of the bike. How much oil does she need in total to fix the bike?
|
Ellie needs 2 wheels * 10ml of oil per wheel = <<2*10=20>>20ml of oil.
To fix the rest of the bike as well, she needs 20 + 5 = <<20+5=25>>25ml of oil.
#### 25
|
Bert bought some unique stamps for his collection. Before the purchase, he had only half the stamps he bought. If he bought 300 stamps, how many stamps does Bert have in total after the purchase?
|
Before the purchase, Bert had 300 * 1/2 = <<300*1/2=150>>150 stamps.
So after the purchase he has 300 + 150 = <<300+150=450>>450 stamps.
#### 450
|
Given that the function $f(x)$ is defined on $\mathbb{R}$ and is not identically zero, and for any real numbers $x$, $y$, it satisfies: $f(2)=2$, $f(xy)=xf(y)+yf(x)$, $a_{n}= \dfrac {f(2^{n})}{2^{n}}(n\in\mathbb{N}^{*})$, $b_{n}= \dfrac {f(2^{n})}{n}(n\in\mathbb{N}^{*})$, consider the following statements:
$(1)f(1)=1$; $(2)f(x)$ is an odd function; $(3)$ The sequence $\{a_{n}\}$ is an arithmetic sequence; $(4)$ The sequence $\{b_{n}\}$ is a geometric sequence.
The correct statements are \_\_\_\_\_\_.
|
(2)(3)(4)
|
Given that $a$ and $b$ are positive numbers, and $a+b=1$, find the value of $a$ when $a=$____, such that the minimum value of the algebraic expression $\frac{{2{a^2}+1}}{{ab}}-2$ is ____.
|
2\sqrt{3}
|
Let $\mathbf{a}, \mathbf{b},$ and $\mathbf{c}$ be vectors such that $\|\mathbf{a}\| = 2,$ $\|\mathbf{b}\| = 3,$ and $\|\mathbf{c}\| = 6,$ and
\[\mathbf{a} + 2\mathbf{b} + \mathbf{c} = \mathbf{0}.\]
Compute $\mathbf{a} \cdot \mathbf{b} + \mathbf{a} \cdot \mathbf{c} + \mathbf{b} \cdot \mathbf{c}.$
|
-19
|
In $\triangle ABC$, $a$, $b$, $c$ are the lengths of the sides opposite to $\angle A$, $\angle B$, $\angle C$ respectively. It is known that $a$, $b$, $c$ are in geometric progression, and $a^{2}-c^{2}=ac-bc$,
(1) Find the measure of $\angle A$;
(2) Find the value of $\frac{b\sin B}{c}$.
|
\frac{\sqrt{3}}{2}
|
When the least common multiple of two positive integers is divided by their greatest common divisor, the result is 33. If one integer is 45, what is the smallest possible value of the other integer?
|
165
|
When Lisa squares her favorite $2$ -digit number, she gets the same result as when she cubes the sum of the digits of her favorite $2$ -digit number. What is Lisa's favorite $2$ -digit number?
|
27
|
The quadratic $8x^2 - 48x - 320$ can be written in the form $a(x+b)^2+c$, where $a$, $b$, and $c$ are constants. What is $a+b+c$?
|
-387
|
If the price of a bag of cherries is $5 when the price of a bag of olives is $7, how much would Jordyn pay for buying 50 bags of each fruit and a 10% discount?
|
At a 10 percent discount, Jordyn will pay 10/100%*$5=$.50 less for a bag of cherries.
To buy one of the cherries at a 10% discount Jordyn will pay $5-$0.50=$<<5-0.5=4.50>>4.50
The cost of buying 50 bags of cherries at the 10% discount is 50*4.50=$<<50*4.50=225>>225
Also, at a 10% discount, Jordyn will pay 10/100*$7=$<<10/100*7=0.70>>0.70 less for a bag of olives.
The price of a bag of olives at a 10% discount is $7-$0.70=$<<7-0.7=6.3>>6.3
To buy 50 bags of olives Jordyn will pay $6.3*50=$<<6.3*50=315>>315
The total cost of buying 50 bags of each fruit at a 10% discount is $315+$225=$540
#### 540
|
Lulu has a quadratic of the form $x^2+bx+44$, where $b$ is a specific positive number. Using her knowledge of how to complete the square, Lulu is able to rewrite this quadratic in the form $(x+m)^2+8$. What is $b$?
|
12
|
In $\triangle PQR$, where $PQ=7$, $PR=9$, $QR=12$, and $S$ is the midpoint of $\overline{QR}$. What is the sum of the radii of the circles inscribed in $\triangle PQS$ and $\triangle PRS$?
A) $\frac{14\sqrt{5}}{13}$
B) $\frac{14\sqrt{5}}{6.5 + \sqrt{29}}$
C) $\frac{12\sqrt{4}}{8.5}$
D) $\frac{10\sqrt{3}}{7 + \sqrt{24}}$
|
\frac{14\sqrt{5}}{6.5 + \sqrt{29}}
|
An abundant number is a positive integer such that the sum of its proper divisors is greater than the number itself. The number 12 is an abundant number since $1 + 2 + 3 + 4 + 6 > 12$. What is the smallest abundant number that is not a multiple of 6?
|
20
|
Point \( O \) is located on side \( AC \) of triangle \( ABC \) such that \( CO : CA = 2 : 3 \). When this triangle is rotated by a certain angle around point \( O \), vertex \( B \) moves to vertex \( C \), and vertex \( A \) moves to point \( D \), which lies on side \( AB \). Find the ratio of the areas of triangles \( BOD \) and \( ABC \).
|
1/6
|
Let $n$ be a given positive integer. Solve the system
\[x_1 + x_2^2 + x_3^3 + \cdots + x_n^n = n,\]
\[x_1 + 2x_2 + 3x_3 + \cdots + nx_n = \frac{n(n+1)}{2}\]
in the set of nonnegative real numbers.
|
(x_1, x_2, \ldots, x_n) = (1, 1, \ldots, 1)
|
Oleg drew an empty 50×50 table and wrote a number above each column and to the left of each row. It turned out that all 100 written numbers are different, 50 of which are rational and the remaining 50 are irrational. Then, in each cell of the table, he recorded the product of the numbers written near its row and its column (a "multiplication table"). What is the maximum number of products in this table that could turn out to be rational numbers?
|
1250
|
Let the natural number $N$ be a perfect square, which has at least three digits, its last two digits are not $00$, and after removing these two digits, the remaining number is still a perfect square. Then, the maximum value of $N$ is ____.
|
1681
|
Given that $\theta$ is an angle in the fourth quadrant, and $\sin\theta + \cos\theta = \frac{1}{5}$, find:
(1) $\sin\theta - \cos\theta$;
(2) $\tan\theta$.
|
-\frac{3}{4}
|
Josiah is three times as old as Hans. Hans is 15 years old now. In three years, what is the sum of the ages of Josiah and Hans?
|
Josiah is 15 x 3 = <<15*3=45>>45 years old now.
In three years, Josiah will be 45 + 3 = <<45+3=48>>48 years old.
Hans will be 15 + 3 = <<15+3=18>>18 years old in three years.
So, the sum of their ages in three years is 48 + 18 = <<48+18=66>>66 years old.
#### 66
|
In rectangle \(ABCD\), \(A B: AD = 1: 2\). Point \(M\) is the midpoint of \(AB\), and point \(K\) lies on \(AD\), dividing it in the ratio \(3:1\) starting from point \(A\). Find the sum of \(\angle CAD\) and \(\angle AKM\).
|
90
|
How many triangles with positive area are there whose vertices are points in the $xy$-plane whose coordinates are integers $(x,y)$ satisfying $1\le x\le 5$ and $1\le y\le 5$?
|
2158
|
Given \( x, y, z \in \mathbf{R} \) such that \( x^2 + y^2 + xy = 1 \), \( y^2 + z^2 + yz = 2 \), \( x^2 + z^2 + xz = 3 \), find \( x + y + z \).
|
\sqrt{3 + \sqrt{6}}
|
Janet has a business selling custom collars for dogs and cats. If it takes 18 inches of nylon to make a dog collar and 10 inches to make a cat collar, how much nylon does she need to make 9 dog collars and 3 cat collars?
|
First find the total number of inches of nylon used for the dog collars: 18 inches/dog collar * 9 dog collars = 162 inches
Then find the total number of inches of nylon used for the cat collars: 10 inches/cat collar * 3 cat collars = 30 inches
Then add the nylon needed for the cat and dog collars to find the total amount needed: 162 inches + 30 inches = <<162+30=192>>192 inches
#### 192
|
Determine the smallest integer $n > 1$ with the property that $n^2(n - 1)$ is divisible by 2009.
|
42
|
Increasing the radius of a cylinder by $4$ units results in an increase in volume by $z$ cubic units. Increasing the height of the cylinder by $10$ units also results in an increase in volume by the same $z$ cubic units. If the original radius is $3$ units, what is the original height of the cylinder?
|
2.25
|
Find the largest possible subset of {1, 2, ... , 15} such that the product of any three distinct elements of the subset is not a square.
|
10
|
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