For the integers x and y, if xy is a multiple of 25, is y a

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[GMAT math practice question]

For the integers x and y, if xy is a multiple of 25, is y a multiple of 5?

1) x-y is a multiple of 5
2) x is a multiple of 2

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Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

The first step of the VA (Variable Approach) method is to modify the original condition and the question, and then recheck the question.

Since xy = 25 =5^2, x is a multiple of 5 or y is a multiple of 5. If x is a multiple of 5, y = x - 5 is also a multiple of 5. Thus the condition 1) is sufficient.

Condition 2)
Since we don't have any information from the condition 2), it is not sufficient.

Therefore, A is the answer.

Answer: A