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2007 AIME I Problems/Problem 1

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Problem

How many positive perfect squares less than 10^6 are multiples of 24?

Solution

The prime factorization of 24 is 2^3\cdot3. Thus, each square must have 3 factors of 2 and 1 factor of 3.

This means that each square is in the form (12c)^2, where c is a positive integer. There are \left\lfloor \frac{1000}{12}\right\rfloor = \boxed{083} solutions.

See also

2007 AIME I (ProblemsResources)
Preceded by
First Question
Followed by
Problem 2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Want to learn how to tackle those tough AMC/AIME/Olympiad algebra problems? Check out Art of Problem Solving's Intermediate Algebra by Richard Rusczyk and Mathew Crawford. Over 1600 problems!
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