2009 AMC 10A Problems/Problem 9
Contents
Problem
Positive integers , , and , with , form a geometric sequence with an integer ratio. What is ?
Solution
The prime factorization of is . As , the ratio must be positive and larger than , hence there is only one possibility: the ratio must be , and then , and .
We know that this is important because the complete equation would be and the only possible outcome for is 7. -Edited slightly by RealityWrites - minor edits by BS2012
See Also
2009 AMC 10A (Problems • Answer Key • Resources) | ||
Preceded by Problem 8 |
Followed by Problem 10 | |
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All AMC 10 Problems and Solutions |
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