olymmath

AIME 2022a

American Invitational Mathematics Examination 2022.

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Problem 1

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Quadratic polynomials P(x)P(x) and Q(x)Q(x) have leading coefficients 22 and −2,-2, respectively. The graphs of both polynomials pass through the two points (16,54)(16,54) and (20,53).(20,53). Find P(0)+Q(0).P(0) + Q(0).

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Problem 2

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

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Problem 3

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In isosceles trapezoid ABCDABCD, parallel bases AB‾\overline{AB} and CD‾\overline{CD} have lengths 500500 and 650650, respectively, and AD=BC=333AD=BC=333. The angle bisectors of ∠A\angle{A} and ∠D\angle{D} meet at PP, and the angle bisectors of ∠B\angle{B} and ∠C\angle{C} meet at QQ. Find PQPQ.

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Problem 4

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Let w=3+i2w = \dfrac{\sqrt{3} + i}{2} and z=−1+i32,z = \dfrac{-1 + i\sqrt{3}}{2}, where i=−1.i = \sqrt{-1}. Find the number of ordered pairs (r,s)(r,s) of positive integers not exceeding 100100 that satisfy the equation i⋅wr=zs.i \cdot w^r = z^s.

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Problem 5

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A straight river that is 264264 meters wide flows from west to east at a rate of 1414 meters per minute. Melanie and Sherry sit on the south bank of the river with Melanie a distance of DD meters downstream from Sherry. Relative to the water, Melanie swims at 8080 meters per minute, and Sherry swims at 6060 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 DD.

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Problem 6

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Find the number of ordered pairs of integers (a,b)(a, b) such that the sequence3,4,5,a,b,30,40,503, 4, 5, a, b, 30, 40, 50is strictly increasing and no set of four (not necessarily consecutive) terms forms an arithmetic progression.

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Problem 7

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Let a,b,c,d,e,f,g,h,ia,b,c,d,e,f,g,h,i be distinct integers from 11 to 9.9. The minimum possible positive value of a⋅b⋅c−d⋅e⋅fg⋅h⋅i\dfrac{a \cdot b \cdot c - d \cdot e \cdot f}{g \cdot h \cdot i} can be written as mn,\frac{m}{n}, where mm and nn are relatively prime positive integers. Find m+n.m+n.

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Problem 8

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Equilateral triangle △ABC\triangle ABC is inscribed in circle ω\omega with radius 18.18. Circle ωA\omega_A is tangent to sides AB‾\overline{AB} and AC‾\overline{AC} and is internally tangent to ω.\omega. Circles ωB\omega_B and ωC\omega_C are defined analogously. Circles ωA,\omega_A, ωB,\omega_B, and ωC\omega_C meet in six points---two points for each pair of circles. The three intersection points closest to the vertices of △ABC\triangle ABC are the vertices of a large equilateral triangle in the interior of △ABC,\triangle ABC, and the other three intersection points are the vertices of a smaller equilateral triangle in the interior of △ABC.\triangle ABC. The side length of the smaller equilateral triangle can be written as a−b,\sqrt{a} - \sqrt{b}, where aa and bb are positive integers. Find a+b.a+b.

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Problem 9

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Ellina has twelve blocks, two each of red (R\textbf{R}), blue (B\textbf{B}), yellow (Y\textbf{Y}), green (G\textbf{G}), orange (O\textbf{O}), and purple (P\textbf{P}). Call an arrangement of blocks even\textit{even} if there is an even number of blocks between each pair of blocks of the same color. For example, the arrangement R B B Y G G Y R O P P O\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 mn,\frac{m}{n}, where mm and nn are relatively prime positive integers. Find m+n.m+n.

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Problem 10

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Three spheres with radii 1111, 1313, and 1919 are mutually externally tangent. A plane intersects the spheres in three congruent circles centered at AA, BB, and CC, respectively, and the centers of the spheres all lie on the same side of this plane. Suppose that AB2=560AB^2 = 560. Find AC2AC^2.

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Problem 11

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Let ABCDABCD be a parallelogram with ∠BAD<90∘.\angle BAD < 90^\circ. A circle tangent to sides DA‾,\overline{DA}, AB‾,\overline{AB}, and BC‾\overline{BC} intersects diagonal AC‾\overline{AC} at points PP and QQ with AP<AQ,AP < AQ, as shown. Suppose that AP=3,AP=3, PQ=9,PQ=9, and QC=16.QC=16. Then the area of ABCDABCD can be expressed in the form mn,m\sqrt{n}, where mm and nn are positive integers, and nn is not divisible by the square of any prime. Find m+n.m+n. [asy] defaultpen(linewidth(0.6)+fontsize(11)); size(8cm); pair A,B,C,D,P,Q; A=(0,0); label("AA", A, SW); B=(6,15); label("BB", B, NW); C=(30,15); label("CC", C, NE); D=(24,0); label("DD", D, SE); P=(5.2,2.6); label("PP", (5.8,2.6), N); Q=(18.3,9.1); label("QQ", (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]

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Problem 12

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For any finite set XX, let ∣X∣| X | denote the number of elements in XX. Define Sn=∑∣A∩B∣,S_n = \sum | A \cap B | , where the sum is taken over all ordered pairs (A,B)(A, B) such that AA and BB are subsets of {1,2,3,⋯ ,n}\left\{ 1 , 2 , 3, \cdots , n \right\} with ∣A∣=∣B∣|A| = |B|. For example, S2=4S_2 = 4 because the sum is taken over the pairs of subsets (A,B)∈{(∅,∅),({1},{1}),({1},{2}),({2},{1}),({2},{2}),({1,2},{1,2})},(A, B) \in \left\{ (\emptyset, \emptyset) , ( \{1\} , \{1\} ), ( \{1\} , \{2\} ) , ( \{2\} , \{1\} ) , ( \{2\} , \{2\} ) , ( \{1 , 2\} , \{1 , 2\} ) \right\} , giving S2=0+1+0+0+1+2=4S_2 = 0 + 1 + 0 + 0 + 1 + 2 = 4. Let S2022S2021=pq\frac{S_{2022}}{S_{2021}} = \frac{p}{q}, where pp and qq are relatively prime positive integers. Find the remainder when p+qp + q is divided by 1000.

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Problem 13

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Let SS be the set of all rational numbers that can be expressed as a repeating decimal in the form 0.abcd‾,0.\overline{abcd}, where at least one of the digits a,a, b,b, c,c, or dd is nonzero. Let NN be the number of distinct numerators obtained when numbers in SS are written as fractions in lowest terms. For example, both 44 and 410410 are counted among the distinct numerators for numbers in SS because 0.3636‾=4110.\overline{3636} = \frac{4}{11} and 0.1230‾=4103333.0.\overline{1230} = \frac{410}{3333}. Find the remainder when NN is divided by 1000.1000.

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Problem 14

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

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Problem 15

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Let x,x, y,y, and zz 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 [(1−x)(1−y)(1−z)]2\left[ (1-x)(1-y)(1-z) \right]^2 can be written as mn,\frac{m}{n}, where mm and nn are relatively prime positive integers. Find m+n.m+n.

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