If x and y are positive integers, is (x/y)^z > 1 ?

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If x and y are positive integers, is (x/y)^z > 1 ?

(1) x - y = -5
(2) z ≠ 0

The OA is E.

Both statements are not sufficient? Why? How can I conclude that the correct option is E?

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by Jay@ManhattanReview » Wed Sep 20, 2017 9:28 pm
Vincen wrote:If x and y are positive integers, is (x/y)^z > 1 ?

(1) x - y = -5
(2) z ≠ 0

The OA is E.

Both statements are not sufficient? Why? How can I conclude that the correct option is E?
Statement 1: x - y = -5

=> A positive integer (y) is subtracted from a positive integer (x), leaving a negative integer (-5); thus, y > x.

Thus, x/y < 1

Case 1: If z is negative. Say z = -1, x = 1 and y = 6, then (x/y)^z = (1/6)^(-1) = 6 > 1. The asnwer is Yes.
Case 2: If z is positive. Say z = 1, x = 1 and y = 6, then (x/y)^z = (1/6)^(1) = 1/6 < 1. The asnwer is No.

No unique answer. Insufficient.

Statement 2: z ≠ 0

Both the cases discussed above are applicable here too. Insufficient.

Statement 1 & 2:

As stated, both the cases discussed above are applicable here too. Insufficient.

The correct answer: E

Hope this helps!

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-Jay
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