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2002 AIME I Problems

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2002 AIME I (Answer Key)
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Instructions

  1. 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.
  2. No aids other than scratch paper, graph paper, ruler, compass, and protractor are permitted. In particular, calculators are not permitted.
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Contents

Problem 1

Many states use a sequence of three letters followed by a sequence of three digits as their standard license-plate pattern. Given that each three-letter three-digit arrangement is equally likely, the probability that such a license plate will contain at least one palindrome (a three-letter arrangement or a three-digit arrangement that reads the same left-to-right as it does right-to-left) is m/n, where m and n are relatively prime positive integers. Find m+n.

Solution

Problem 2

The diagram shows twenty congruent circles arranged in three rows and enclosed in a rectangle. The circles are tangent to one another and to the sides of the rectangle as shown in the diagram. The ratio of the longer dimension of the rectangle to the shorter dimension can be written as \frac{1}{2}\left(\sqrt{p}-q\right), where p and q are positive integers. Find p+q.

AIME 2002I Problem 02.png

Solution

Problem 3

Jane is 25 years old. Dick is older than Jane. In n years, where n is a positive integer, Dick's age and Jane's age will both be two-digit number and will have the property that Jane's age is obtained by interchanging the digits of Dick's age. Let d be Dick's present age. How many ordered pairs of positive integers (d,n) are possible?

Solution

Problem 4

Consider the sequence defined by a_k=\frac 1{k^2+k} for k\ge 1. Given that a_m+a_{m+1}+\cdots+a_{n-1}=1/29, for positive integers m and n with m<n, find m+n.

Solution

Problem 5

Let A_1, A_2, A_3, \ldots, A_{12} be the vertices of a regular dodecagon. How many distinct squares in the plane of the dodecagon have at least two vertices in the set \{A_1,A_2,A_3,\ldots,A_{12}\}?

Solution

Problem 6

The solutions to the system of equations

\begin{eqnarray*} \log_{225}{x}+\log_{64}{y} &=& 4\\ \log_x{225}-\log_y{64} &=& 1 \end{eqnarray*}

are (x_1,y_1) and (x_2, y_2). Find \log_{30}{(x_1y_1x_2y_2)}.

Solution

Problem 7

The Binomial Expansion is valid for exponents that are not integers. That is, for all real numbers x, y, and r with |x|>|y|,
(x+y)^r=x^r+rx^{r-1}y^1+\frac{r(r-1)}2x^{r-2}y^2+\frac{r(r-1)(r-2)}{3!}x^{r-3}y^3+\cdots

What are the first three digits to the right of the decimal point in the decimal representation of \left(10^{2002}+1\right)^{10/7}?

Solution

Problem 8

Find the smallest integer k for which the conditions

(1) a_1, a_2, a_3, \ldots is a nondecreasing sequence of positive integers

(2) a_n=a_{n-1}+a_{n-2} for all n>2

(3) a_9=k

are satisfied by more than one sequence.

Solution

Problem 9

Harold, Tanya, and Ulysses paint a very long picket fence. Harold starts with the first picket and paints every hth picket; Tanya starts with the second picket and paints every tth picket; and Ulysses starts with the third picket and paints every uth picket. Call the positive integer 100h+10t+u \textit{paintable} when the triple (h,t,u) of positive integers results in every picket being painted exactly once. Find the sum of all the paintable integers.

Solution

Problem 10

In the diagram below, angle ABC is a right angle. Point D is on \overline{BC}, and \overline{AD} bisects angle CAB. Points E and F are on \overline{AB} and \overline{AC}, respectively, so that AE=3 and AF=10. Given that EB=9 and FC=27, find the integer closest to the area of quadrilateral DCFG.

AIME 2002I Problem 10.png

Solution

Problem 11

Let ABCD and BCFG be two faces of a cube with AB=12. A beam of light emanates from vertex A and reflects off face BCFG at point P, which is 7 units from \overline{BG} and 5 units from \overline{BC}. The beam continues to be reflected off the faces of the cube. The length of the light path from the time it leaves point A until it next reaches a vertex of the cube is given by m\sqrt{n}, where m and n are integers and n is not divisible by the square of any prime. Find m+n.

Solution

Problem 12

Let F(z)=\frac{z+i}{z-i} for all complex numbers z\not= i, and let z_n=F(z_{n-1}) for all positive integers n. Given that z_0=\frac 1{137}+i and z_{2002}=a+bi, where a and b are real numbers, find a+b.

Solution

Problem 13

In triangle ABC the medians \overline{AD} and \overline{CE} have lengths 18 and 27, respectively, and AB = 24. Extend \overline{CE} to intersect the circumcircle of ABC at F. The area of triangle AFB is m\sqrt {n}, where m and n are positive integers and n is not divisible by the square of any prime. Find m + n.

Solution

Problem 14

A set \mathcal{S} of distinct positive integers has the following property: for every integer x in \mathcal{S}, the arithmetic mean of the set of values obtained by deleting x from \mathcal{S} is an integer. Given that 1 belongs to \mathcal{S} and that 2002 is the largest element of \mathcal{S}, what is the greatest number of elements that \mathcal{S} can have?

Solution

Problem 15

Polyhedron ABCDEFG has six faces. Face ABCD is a square with AB = 12; face ABFG is a trapezoid with \overline{AB} parallel to \overline{GF}, BF = AG = 8, and GF = 6; and face CDE has CE = DE = 14. The other three faces are ADEG, BCEF, and EFG. The distance from E to face ABCD is 12. Given that EG^2 = p - q\sqrt {r}, where p, q, and r are positive integers and r is not divisible by the square of any prime, find p + q + r.

Solution

See also