Difference between revisions of "2022 AIME I Problems"

Latest revision as of 18:06, 2 January 2023

2022 AIME I (Answer Key) Printable version \| AoPS Contest Collections • PDF
Instructions This is a 15-question, 3-hour examination. All answers are integers ranging from $000$ to $999$ , inclusive. Your score will be the number of correct answers; i.e., there is neither partial credit nor a penalty for wrong answers. No aids other than scratch paper, graph paper, ruler, compass, and protractor are permitted. In particular, calculators and computers are not permitted.
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15

Problem 1

Quadratic polynomials $P(x)$ and $Q(x)$ have leading coefficients $2$ and $-2,$ respectively. The graphs of both polynomials pass through the two points $(16,54)$ and $(20,53).$ Find $P(0) + Q(0).$

Solution

Problem 2

Find the three-digit positive integer $\underline{a}\,\underline{b}\,\underline{c}$ whose representation in base nine is $\underline{b}\,\underline{c}\,\underline{a}_{\,\text{nine}},$ where $a,$ $b,$ and $c$ are (not necessarily distinct) digits.

Solution

Problem 3

In isosceles trapezoid $ABCD,$ parallel bases $\overline{AB}$ and $\overline{CD}$ have lengths $500$ and $650,$ respectively, and $AD=BC=333.$ The angle bisectors of $\angle A$ and $\angle D$ meet at $P,$ and the angle bisectors of $\angle B$ and $\angle C$ meet at $Q.$ Find $PQ.$

Solution

Problem 4

Let $w = \dfrac{\sqrt{3} + i}{2}$ and $z = \dfrac{-1 + i\sqrt{3}}{2},$ where $i = \sqrt{-1}.$ Find the number of ordered pairs $(r,s)$ of positive integers not exceeding $100$ that satisfy the equation $i \cdot w^r = z^s.$

Solution

Problem 5

A straight river that is $264$ meters wide flows from west to east at a rate of $14$ meters per minute. Melanie and Sherry sit on the south bank of the river with Melanie a distance of $D$ meters downstream from Sherry. Relative to the water, Melanie swims at $80$ meters per minute, and Sherry swims at $60$ meters per minute. At the same time, Melanie and Sherry begin swimming in straight lines to a point on the north bank of the river that is equidistant from their starting positions. The two women arrive at this point simultaneously. Find $D.$

Solution

Problem 6

Find the number of ordered pairs of integers $(a,b)$ such that the sequence $3,4,5,a,b,30,40,50$ is strictly increasing and no set of four (not necessarily consecutive) terms forms an arithmetic progression.

Solution

Problem 7

Let $a,b,c,d,e,f,g,h,i$ be distinct integers from $1$ to $9.$ The minimum possible positive value of $\dfrac{a \cdot b \cdot c - d \cdot e \cdot f}{g \cdot h \cdot i}$ can be written as $\frac{m}{n},$ where $m$ and $n$ are relatively prime positive integers. Find $m+n.$

Solution

Problem 8

Equilateral triangle $\triangle ABC$ is inscribed in circle $\omega$ with radius $18.$ Circle $\omega_A$ is tangent to sides $\overline{AB}$ and $\overline{AC}$ and is internally tangent to $\omega.$ Circles $\omega_B$ and $\omega_C$ are defined analogously. Circles $\omega_A,$ $\omega_B,$ and $\omega_C$ meet in six points---two points for each pair of circles. The three intersection points closest to the vertices of $\triangle ABC$ are the vertices of a large equilateral triangle in the interior of $\triangle ABC,$ and the other three intersection points are the vertices of a smaller equilateral triangle in the interior of $\triangle ABC.$ The side length of the smaller equilateral triangle can be written as $\sqrt{a} - \sqrt{b},$ where $a$ and $b$ are positive integers. Find $a+b.$

Solution

Problem 9

Ellina has twelve blocks, two each of red ( $\textbf{R}$ ), blue ( $\textbf{B}$ ), yellow ( $\textbf{Y}$ ), green ( $\textbf{G}$ ), orange ( $\textbf{O}$ ), and purple ( $\textbf{P}$ ). Call an arrangement of blocks $\textit{even}$ if there is an even number of blocks between each pair of blocks of the same color. For example, the arrangement $\textbf{R B B Y G G Y R O P P O}$ is even. Ellina arranges her blocks in a row in random order. The probability that her arrangement is even is $\frac{m}{n},$ where $m$ and $n$ are relatively prime positive integers. Find $m+n.$

Solution

Problem 10

Three spheres with radii $11,$ $13,$ and $19$ are mutually externally tangent. A plane intersects the spheres in three congruent circles centered at $A,$ $B,$ and $C,$ respectively, and the centers of the spheres all lie on the same side of this plane. Suppose that $AB^2 = 560.$ Find $AC^2.$

Solution

Problem 11

Let $ABCD$ be a parallelogram with $\angle BAD < 90^\circ.$ A circle tangent to sides $\overline{DA},$ $\overline{AB},$ and $\overline{BC}$ intersects diagonal $\overline{AC}$ at points $P$ and $Q$ with $AP < AQ,$ as shown. Suppose that $AP=3,$ $PQ=9,$ and $QC=16.$ Then the area of $ABCD$ can be expressed in the form $m\sqrt{n},$ where $m$ and $n$ are positive integers, and $n$ is not divisible by the square of any prime. Find $m+n.$

$[asy] defaultpen(linewidth(0.6)+fontsize(11)); size(8cm); pair A,B,C,D,P,Q; A=(0,0); label("$A$", A, SW); B=(6,15); label("$B$", B, NW); C=(30,15); label("$C$", C, NE); D=(24,0); label("$D$", D, SE); P=(5.2,2.6); label("$P$", (5.8,2.6), N); Q=(18.3,9.1); label("$Q$", (18.1,9.7), W); draw(A--B--C--D--cycle); draw(C--A); draw(Circle((10.95,7.45), 7.45)); dot(A^^B^^C^^D^^P^^Q); [/asy]$

Solution

Problem 12

For any finite set $X,$ let $|X|$ denote the number of elements in $X.$ Define $S_n = \sum |A \cap B|,$ where the sum is taken over all ordered pairs $(A,B)$ such that $A$ and $B$ are subsets of $\{1,2,3,\ldots,n\}$ with $|A|=|B|.$ For example, $S_2 = 4$ because the sum is taken over the pairs of subsets $(A,B) \in \left\{(\emptyset,\emptyset),(\{1\},\{1\}),(\{1\},\{2\}),(\{2\},\{1\}),(\{2\},\{2\}),(\{1,2\},\{1,2\})\right\},$ giving $S_2 = 0+1+0+0+1+2=4.$ Let $\frac{S_{2022}}{S_{2021}} = \frac{p}{q},$ where $p$ and $q$ are relatively prime positive integers. Find the remainder when $p+q$ is divided by $1000.$

Solution

Problem 13

Let $S$ be the set of all rational numbers that can be expressed as a repeating decimal in the form $0.\overline{abcd},$ where at least one of the digits $a,$ $b,$ $c,$ or $d$ is nonzero. Let $N$ be the number of distinct numerators obtained when numbers in $S$ are written as fractions in lowest terms. For example, both $4$ and $410$ are counted among the distinct numerators for numbers in $S$ because $0.\overline{3636} = \frac{4}{11}$ and $0.\overline{1230} = \frac{410}{3333}.$ Find the remainder when $N$ is divided by $1000.$

Solution

Problem 14

Given $\triangle ABC$ and a point $P$ on one of its sides, call line $\ell$ the $\textit{splitting line}$ of $\triangle ABC$ through $P$ if $\ell$ passes through $P$ and divides $\triangle ABC$ into two polygons of equal perimeter. Let $\triangle ABC$ be a triangle where $BC = 219$ and $AB$ and $AC$ are positive integers. Let $M$ and $N$ be the midpoints of $\overline{AB}$ and $\overline{AC},$ respectively, and suppose that the splitting lines of $\triangle ABC$ through $M$ and $N$ intersect at $30^\circ.$ Find the perimeter of $\triangle ABC.$

Solution

Problem 15

Let $x,$ $y,$ and $z$ be positive real numbers satisfying the system of equations: $\begin{align*} \sqrt{2x-xy} + \sqrt{2y-xy} &= 1 \\ \sqrt{2y-yz} + \sqrt{2z-yz} &= \sqrt2 \\ \sqrt{2z-zx} + \sqrt{2x-zx} &= \sqrt3. \end{align*}$ Then $\left[ (1-x)(1-y)(1-z) \right]^2$ can be written as $\frac{m}{n},$ where $m$ and $n$ are relatively prime positive integers. Find $m+n.$

Solution

@@ Line 38: / Line 38: @@
 ==Problem 7==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Let <math>a,b,c,d,e,f,g,h,i</math> be distinct integers from <math>1</math> to <math>9.</math> The minimum possible positive value of <cmath>\dfrac{a \cdot b \cdot c - d \cdot e \cdot f}{g \cdot h \cdot i}</cmath> can be written as <math>\frac{m}{n},</math> where <math>m</math> and <math>n</math> are relatively prime positive integers. Find <math>m+n.</math>
 [[2022 AIME I Problems/Problem 7|Solution]]
 ==Problem 8==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Equilateral triangle <math>\triangle ABC</math> is inscribed in circle <math>\omega</math> with radius <math>18.</math> Circle <math>\omega_A</math> is tangent to sides <math>\overline{AB}</math> and <math>\overline{AC}</math> and is internally tangent to <math>\omega.</math> Circles <math>\omega_B</math> and <math>\omega_C</math> are defined analogously. Circles <math>\omega_A,</math> <math>\omega_B,</math> and <math>\omega_C</math> meet in six points---two points for each pair of circles. The three intersection points closest to the vertices of <math>\triangle ABC</math> are the vertices of a large equilateral triangle in the interior of <math>\triangle ABC,</math> and the other three intersection points are the vertices of a smaller equilateral triangle in the interior of <math>\triangle ABC.</math> The side length of the smaller equilateral triangle can be written as <math>\sqrt{a} - \sqrt{b},</math> where <math>a</math> and <math>b</math> are positive integers. Find <math>a+b.</math>
 [[2022 AIME I Problems/Problem 8|Solution]]
 ==Problem 9==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Ellina has twelve blocks, two each of red (<math>\textbf{R}</math>), blue (<math>\textbf{B}</math>), yellow (<math>\textbf{Y}</math>), green (<math>\textbf{G}</math>), orange (<math>\textbf{O}</math>), and purple (<math>\textbf{P}</math>). Call an arrangement of blocks <math>\textit{even}</math> if there is an even number of blocks between each pair of blocks of the same color. For example, the arrangement
+<cmath>\textbf{R B B Y G G Y R O P P O}</cmath>
+is even. Ellina arranges her blocks in a row in random order. The probability that her arrangement is even is <math>\frac{m}{n},</math> where <math>m</math> and <math>n</math> are relatively prime positive integers. Find <math>m+n.</math>
 [[2022 AIME I Problems/Problem 9|Solution]]
 ==Problem 10==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Three spheres with radii <math>11,</math> <math>13,</math> and <math>19</math> are mutually externally tangent. A plane intersects the spheres in three congruent circles centered at <math>A,</math> <math>B,</math> and <math>C,</math> respectively, and the centers of the spheres all lie on the same side of this plane. Suppose that <math>AB^2 = 560.</math> Find <math>AC^2.</math>
 [[2022 AIME I Problems/Problem 10|Solution]]
 ==Problem 11==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Let <math>ABCD</math> be a parallelogram with <math>\angle BAD < 90^\circ.</math> A circle tangent to sides <math>\overline{DA},</math> <math>\overline{AB},</math> and <math>\overline{BC}</math> intersects diagonal <math>\overline{AC}</math> at points <math>P</math> and <math>Q</math> with <math>AP < AQ,</math> as shown. Suppose that <math>AP=3,</math> <math>PQ=9,</math> and <math>QC=16.</math> Then the area of <math>ABCD</math> can be expressed in the form <math>m\sqrt{n},</math> where <math>m</math> and <math>n</math> are positive integers, and <math>n</math> is not divisible by the square of any prime. Find <math>m+n.</math>
+<asy>
+defaultpen(linewidth(0.6)+fontsize(11));
+size(8cm);
+pair A,B,C,D,P,Q;
+A=(0,0);
+label("$A$", A, SW);
+B=(6,15);
+label("$B$", B, NW);
+C=(30,15);
+label("$C$", C, NE);
+D=(24,0);
+label("$D$", D, SE);
+P=(5.2,2.6);
+label("$P$", (5.8,2.6), N);
+Q=(18.3,9.1);
+label("$Q$", (18.1,9.7), W);
+draw(A--B--C--D--cycle);
+draw(C--A);
+draw(Circle((10.95,7.45), 7.45));
+dot(A^^B^^C^^D^^P^^Q);
+</asy>
 [[2022 AIME I Problems/Problem 11|Solution]]
 ==Problem 12==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+For any finite set <math>X,</math> let <math>|X|</math> denote the number of elements in <math>X.</math> Define <cmath>S_n = \sum |A \cap B|,</cmath> where the sum is taken over all ordered pairs <math>(A,B)</math> such that <math>A</math> and <math>B</math> are subsets of <math>\{1,2,3,\ldots,n\}</math> with <math>|A|=|B|.</math> For example, <math>S_2 = 4</math> because the sum is taken over the pairs of subsets <cmath>(A,B) \in \left\{(\emptyset,\emptyset),(\{1\},\{1\}),(\{1\},\{2\}),(\{2\},\{1\}),(\{2\},\{2\}),(\{1,2\},\{1,2\})\right\},</cmath> giving <math>S_2 = 0+1+0+0+1+2=4.</math> Let <math>\frac{S_{2022}}{S_{2021}} = \frac{p}{q},</math> where <math>p</math> and <math>q</math> are relatively prime positive integers. Find the remainder when <math>p+q</math> is divided by <math>1000.</math>
 [[2022 AIME I Problems/Problem 12|Solution]]
 ==Problem 13==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Let <math>S</math> be the set of all rational numbers that can be expressed as a repeating decimal in the form <math>0.\overline{abcd},</math> where at least one of the digits <math>a,</math> <math>b,</math> <math>c,</math> or <math>d</math> is nonzero. Let <math>N</math> be the number of distinct numerators obtained when numbers in <math>S</math> are written as fractions in lowest terms. For example, both <math>4</math> and <math>410</math> are counted among the distinct numerators for numbers in <math>S</math> because <math>0.\overline{3636} = \frac{4}{11}</math> and <math>0.\overline{1230} = \frac{410}{3333}.</math> Find the remainder when <math>N</math> is divided by <math>1000.</math>
 [[2022 AIME I Problems/Problem 13|Solution]]
 ==Problem 14==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Given <math>\triangle ABC</math> and a point <math>P</math> on one of its sides, call line <math>\ell</math> the <math>\textit{splitting line}</math> of <math>\triangle ABC</math> through <math>P</math> if <math>\ell</math> passes through <math>P</math> and divides <math>\triangle ABC</math> into two polygons of equal perimeter. Let <math>\triangle ABC</math> be a triangle where <math>BC = 219</math> and <math>AB</math> and <math>AC</math> are positive integers. Let <math>M</math> and <math>N</math> be the midpoints of <math>\overline{AB}</math> and <math>\overline{AC},</math> respectively, and suppose that the splitting lines of <math>\triangle ABC</math> through <math>M</math> and <math>N</math> intersect at <math>30^\circ.</math> Find the perimeter of <math>\triangle ABC.</math>
 [[2022 AIME I Problems/Problem 14|Solution]]
 ==Problem 15==
-<cmath>\textbf{Please do not post this problem until the contest is released.}</cmath>
+Let <math>x,</math> <math>y,</math> and <math>z</math> be positive real numbers satisfying the system of equations:
+<cmath>\begin{align*}
+\sqrt{2x-xy} + \sqrt{2y-xy} &= 1 \\
+\sqrt{2y-yz} + \sqrt{2z-yz} &= \sqrt2 \\
+\sqrt{2z-zx} + \sqrt{2x-zx} &= \sqrt3.
+\end{align*}</cmath>
+Then <math>\left[ (1-x)(1-y)(1-z) \right]^2</math> can be written as <math>\frac{m}{n},</math> where <math>m</math> and <math>n</math> are relatively prime positive integers. Find <math>m+n.</math>
 [[2022 AIME I Problems/Problem 15|Solution]]
-==See also==
+==See Also==
 {{AIME box|year=2022|n=I|before=[[2021 AIME II Problems|2021 AIME II]]|after=[[2022 AIME II Problems|2022 AIME II]]}}
 * [[American Invitational Mathematics Examination]]

2022 AIME I (Problems • Answer Key • Resources)
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Difference between revisions of "2022 AIME I Problems"

Latest revision as of 18:06, 2 January 2023

Contents

Problem 1

Problem 2

Problem 3

Problem 4

Problem 5

Problem 6

Problem 7

Problem 8

Problem 9

Problem 10

Problem 11

Problem 12

Problem 13

Problem 14

Problem 15

See Also