If x and y are positive, is x < 10 < y ?
(1) x < y and xy = 100
(2) x^2 < 100 < y^2
Official Guide question
Answer: D
(1) x < y and xy = 100
(2) x^2 < 100 < y^2
Official Guide question
Answer: D
Hi jjjinapinch,
We're told that X and Y are POSITIVE. We're asked if X < 10 < Y. This is a YES/NO question. We can solve it with a mix of TESTing VALUES and Number Properties.
1) X < Y and (X)(Y) = 100
With the information in Fact 1, we know that X and Y cannot be the same value (X < Y). IF they were the same value, then we would have (10)(10) = 100. Since that's NOT possible though - and both variables are POSITIVE - the only option is for X to DECREASE from 10 and Y to INCREASE from 10. Thus, the answer to the question is ALWAYS YES.
Fact 1 is SUFFICIENT
2) X^2 < 100 < Y^2
Since both variables are POSITIVE, we know that X MUST be less than 10 and that Y MUST be greater than 10. Thus, the answer to the question is ALWAYS YES.
Fact 2 is SUFFICIENT
Final Answer: D
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