Problem:
The product of three positive numbers is , their sum is greater than the sum of their inverses. Prove that just one of the numbers is greater than .
Solution
Solution:
The product of the numbers is , so they cannot all be greater than or all less than . If all equalled , then the sum would not be greater than the sum of the inverses. So we must have either one or two greater than . Thus it is sufficient to show that we cannot have two of the numbers greater than .
Suppose that , . Then since , we have , and hence . Dividing by gives . Contradiction.
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