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DS - 65

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victory
 Post subject: DS - 65
 Post Posted: Thu Nov 15, 2007 7:48 pm 
Q. if m is an integer, is m odd?

(1) m/2 is NOT an even integer
(2) m-3 is an even integer

Ans: Correct B
explaination
(1) since m could be either the odd integer 3 or the even integer 10 and still satisfy this condition, there is no information to definately show where m is odd or even, NOT sufficient

My question:
While substituting values for m, if m = 3, 3/2 = NOT an INTEGER, why does the solution refers to value of m = 3 as a good value for m? I was only substituting values for m such that m/2 would not be even AND would be an integer?
So I had values of m that qualify as 2, 5, 10, 14.. etc and I said stat (1) is sufficient! Can someone please help? What I am I missing here?
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victory
 Post subject: Re: DS - 65 (edited)
 Post Posted: Thu Nov 15, 2007 7:51 pm 
victory wrote:
Q. if m is an integer, is m odd?

(1) m/2 is NOT an even integer
(2) m-3 is an even integer

Ans: Correct B
explaination
(1) since m could be either the odd integer 3 or the even integer 10 and still satisfy this condition, there is no information to definately show where m is odd or even, NOT sufficient

My question:
While substituting values for m, if m = 3, 3/2 = NOT an INTEGER, why does the solution refers to value of m = 3 as a good value for m? I was only substituting values for m such that m/2 would not be even AND would be an integer?
So I had values of m that qualify as 2, 6, 10, 14.. etc and I said stat (1) is sufficient! Can someone please help? What I am I missing here?
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RonPurewal
 Post subject:
 Post Posted: Fri Nov 16, 2007 7:30 am 
Offline
ManhattanGMAT Staff


Posts: 6765
You're currently reading the answer choice incorrectly. As an analogy, take the following:

(1) X is not a blonde woman

I satisfy this criterion, because I'm a man and I have dark hair. If you substitute 'integer' for 'woman' and 'even' for 'blonde', you'll see the fallacy in your logic: you'd be saying that I don't satisfy (1), 'not a blonde woman', because I'm not a woman. Not so: if EITHER I'm a man OR I have dark hair, then I'm included in this description.

To satisfy (1) it is enough EITHER that m/2 is not even, OR that m/2 is not an integer at all. So values like m = 3, 5, ... are fine.
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