-
soniadiana2011
- Junior | Next Rank: 30 Posts
- Posts: 14
- Joined: Wed May 16, 2012 8:52 am
Prompt: If m is an integer, is m odd?
Straightforward yes/no prompt.
(1) m/2 is not an even integer.
Well, "not an even integer" is a big category --- that could mean
(a) an odd integer ---> m/2 = 3 ---> m = 6, which is even,
or
(b) not an integer at all ---> m/2 = 5/2 ---> m = 5, which is odd
We can devise scenarios consistent with this statement that give both answers to the prompt question, so this statement, by itself, is insufficient.
(2) m - 3 is an even integer
We know m is an integer. If m - 3 = even, then 3 + (even) = m
We know (odd) + (even) = (odd), so if m = 3 + (even), m must be odd.
Examples: let m - 3 equal even integers
m - 3 = 2 ---> m = 5
m - 3 = 4 ---> m = 7
m - 3 = 6 ---> m = 9
m - 3 = 8 ---> m = 11
By both logic and by numerical plug-in, it's clear that m must be odd. Therefore, statement #2 is sufficient.
Answer = B
Here's a blog you may find helpful.
https://magoosh.com/gmat/2012/integer-pr ... ion-topic/
Does all this make sense? Let me know if you have any further questions.
Mike
