1st AIME 1983

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1.  x, y, z are real numbers greater than 1 and w is a positive real number. If logxw = 24, logyw = 40 and logxyzw = 12, find logzw.
2.  Find the minimum value of |x - p| + |x - 15| + |x - p - 15| for x in the range p ≤ x ≤ 15, where 0 < p < 15.
3.  Find the product of the real roots of the equation x2 + 18x + 30 = 2 √(x2 + 18x + 45).
4.  A and C lie on a circle center O with radius √50. The point B inside the circle is such that ∠ABC = 90o, AB = 6, BC = 2. Find OB.

5.  w and z are complex numbers such that w2 + z2 = 7, w3 + z3 = 10. What is the largest possible real value of w + z?
6.  What is the remainder on dividing 683 + 883 by 49?
7.  25 knights are seated at a round table and 3 are chosen at random. Find the probability that at least two of the chosen 3 are sitting next to each other.
8.  What is the largest 2-digit prime factor of the binomial coefficient 200C100?
9.  Find the minimum value of (9x2sin2x + 4)/(x sin x) for 0 < x < π.
10.  How many 4 digit numbers with first digit 1 have exactly two identical digits (like 1447, 1005 or 1231)?
11.  ABCD is a square side 6√2. EF is parallel to the square and has length 12√2. The faces BCF and ADE are equilateral. What is the volume of the solid ABCDEF?

12.  The chord CD is perpendicular to the diameter AB and meets it at H. The distances AB and CD are integral. The distance AB has 2 digits and the distance CD is obtained by reversing the digits of AB. The distance OH is a non-zero rational. Find AB.

13.  For each non-empty subset of {1, 2, 3, 4, 5, 6, 7} arrange the members in decreasing order with alternating signs and take the sum. For example, for the subset {5} we get 5. For {6, 3, 1} we get 6 - 3 + 1 = 4. Find the sum of all the resulting numbers.
14.  The distance AB is 12. The circle center A radius 8 and the circle center B radius 6 meet at P (and another point). A line through P meets the circles again at Q and R (with Q on the larger circle), so that QP = PR. Find QP2.

15.  BC is a chord length 6 of a circle center O radius 5. A is a point on the circle closer to B than C such that there is just one chord AD which is bisected by BC. Find sin AOB.

Answers

To avoid possible copyright problems, I have changed the wording, but not the substance, of the problems.

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© John Scholes
jscholes@kalva.demon.co.uk
14 March 2003
Last updated/corrected 26 Nov 03