Mock AIME 2 Pre 2005 Problems/Problem 5
Problem
Let be the set of integers for which , an infinite decimal that has the property that for all positive integers . Given that is prime, how many positive integers are in ? (The are digits.)
Solution
Let , the first decimal digits of . We can see that so is the set that contains all divisors of except for . Since the number has divisors and our answer is
-MP8148
See also
Mock AIME 2 Pre 2005 (Problems, Source) | ||
Preceded by Problem 4 |
Followed by Problem 6 | |
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