DS: Even integer?

[tsotnemir]

Is product 2*x*5*y an even integer?

1. 2 + x + 5 + y is an even integer
2. x - y is an odd integer

My answer is C, but like to hear other opinion and way of thinking.

Thanks.

[Kweku.Amoako]

is this a GMAT question? what is the source?

An even number multiplied by any integer will always be even..

since the product 2*x*5*y has the even number 2, this product will always be even unless the product of x and y is not an integer.

Hence I can rephrase: is x*y = integer ?

1) 2+x+5+y or 7+x+y is even. This implies x+y is odd

2.5 +2.5 = 5(odd) but 2.5*2.5 is not an integer
whereas 3+2 = 5 and 3*2 = 6 integer

Hence this is insufficient

2) x-y is odd.

4.5 - 2.5 = 1 but 3.5* 2.5 is not an integer
4-3 = 1 and 4*3 is an integer

Hence this is also insufficient

3) x+y = odd and x - y = odd. Well if x+y is odd then x-y should also be odd so this does not add addtional info. My answer will be E

Let me know if this is right

[RonPurewal]

Is product 2*x*5*y an even integer?

1. 2 + x + 5 + y is an even integer
2. x - y is an odd integer

My answer is C, but like to hear other opinion and way of thinking.

Thanks.

please give the SOURCE of this question. we'll delete the question within a week or two if you don't.

** NOTE: ANOTHER FORUM DOES NOT COUNT AS THE SOURCE. you need the actual, original source of the problem. **

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in any case, yeah, this should be (e). you have to realize that x and y don't have to be integers.

in fact, they CAN'T be required to be integers. if they were, then you'd already have the answer to the problem without either statement. (if they were both integers, then ANY product with a "2" would automatically be even.)
there are no problems that are already sufficient without the statements, so that wouldn't be ok.