gmatprep09 wrote:

If a , b, and c are integers and ab^2/c is a positive even integer, which of the following must be true?

I. ab is even

II. ab > 0

III. c is even

I only

II only

I and II

I and III

I, II, and III

ab^2/c = 2k where k is any +ve integer.

I. ab is even - true: Since 2k is even, either of a or b must be even. Any odd (if ab^2 is odd) divided by any integer (c must be odd) never results in even. So either a or b must be even.

II. ab > 0 - Not true: If a and c are +ve, and b is -ve, 2k is +ve and ab 0.

III. c is even - Not true: If a = 5, b = 4 and c = 1, 2k is even. If a = 4, b = 4 and c = 4, 2k is even. So C is not necessarily an even.

Only I is correct.

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