Consider two statements
If X is an integer and where p is not an integer.
If Y is an integer and where q is not an integer
Which of the following correctly specifies the Even/Odd nature of X and Y respectively
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I think the trick is that for Y, if q is not an integer, Y=2q could be even? Wait, no. If Y is even, then Y=2k for integer k, so q=k, which is integer. Contradiction. So Y cannot be even. So Y must be odd. Similarly for X, if p is not integer, 2p is even, so X is odd. So both odd. But the answer is C? That's weird. Maybe I'm missing something. Can someone clarify?
I think there might be a typo in the question. The credited answer is (C) Even, Odd. But based on the statements, X should be odd and Y should be odd. So (B) seems correct. Maybe the question meant 'p is an integer' for X? Or maybe it's a different version? I'd go with B if I saw this on the exam.
This is a good one. The key is to realize that if Y=2q and Y is integer, then q must be either integer or half-integer. But q is not integer, so q is half-integer, making Y odd. For X, if p is not integer, 2p is even, so X is odd. So both odd. But the answer is C? That's odd. Maybe the question meant 'p is an integer'? If p is integer, then 2p is even, X odd. If q is not integer, Y odd. Still both odd. Hmm. I think the answer should be B, but the site says C. I'll go with the site's answer for practice, but I'm skeptical.
What it tests
Your command of divisibility, primes, factors, parity, and how the GMAT tests properties of integers.
Common trap
Forgetting that 1 is not prime, that 0 is divisible by every integer, or that negative numbers flip your assumptions.