Hi All,
Questions that involve factors and multiples are essentially about patterns, so TESTing VALUES is a great approach (and once you can prove the pattern, then you can stop working). In these situations, it's important to be thorough (and make sure that you consider the simplest ideas first).
Here, we're told that M and N are NON-0 INTEGERS. We're asked if M/N is an integer. This is a YES/NO question.
Fact 1: 2M is divisible by N.
IF....
M = 1
2 is divisible by N
IF....
N = 1
then M/N = 1/1 and the answer to the question is YES.
N = 2
then M/N = 1/2 and the answer to the question is NO.
Fact 1 is INSUFFICIENT.
Fact 2: M is divisible by 2N
IF....
M = 2
2 is divisible by 2N
N = 1
then M/N = 2/1 and the answer to the question is YES.
IF...
M = 4
4 is divisible by 2N
N = 1
then M/N = 4/1 and the answer to the question is YES.
N = 2
then M/N = 4/2 and the answer to the question is YES.
You should notice the pattern here. Since the question asks us to focus on M/N....if M is divisible by 2N, then it WILL be divisible by N.
Fact 2 is SUFFICIENT.
Final Answer:
GMAT assassins aren't born, they're made,
Rich
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