GMAT Prep #2 DS: If x and y are integers and x>0, is y>0?

[judychuang]

If x and y are integers and x>0, is y>0?

1) 7x-2y>0
2) -y<x

Answer is E

I searched the forum, and couldn't find an explanation.

Help?

Thanks!

[jnelson0612]

If x and y are integers and x>0, is y>0?

1) 7x-2y>0
2) -y>x

Answer is E

I searched the forum, and couldn't find an explanation.

Help?

Thanks!

Hi Judy!
Are you sure that this problem is written correctly? With statement 1, we can plug numbers and find that y could be both positive or negative, so statement 1 would be insufficient.

However, statement 2 says -y>x. If we know that x is positive, then y MUST be negative to allow y to be greater than x after the additional negative sign is applied. I cannot think of another situation in which anything else could be the case.

Please let us know--thanks!

[krishnan.anju1987]

I thought the second statement said -y<x which means since x is positive for -y to be less than x, y could be either positive or if negative then a number such that |y|<|x|. Did I misunderstand something here?

[tim]

|y| < |x| may be too strong of a statement; go back and check your work..

[krishnan.anju1987]

Maybe I am making a mistake here and am unable to see it but as I see it this is how it goes.

a) 7x-2y>0
x is positive. Now if Y is positive then

y<7x/2

also y can be any negative value to satisfy this equation. Hence, Insufficient.

b) -y<x
here x is positive.

Now this is possible for any positive value of y.
If y is negative then for a value such that |y|<|x|, this statement will be true. Hence, Insufficient.

Taking both the statements together
y could still be positive or negative.

Hence answer is E.

It would be great in case someone could confirm my reasoning.

[RonPurewal]

Maybe I am making a mistake here and am unable to see it but as I see it this is how it goes.

a) 7x-2y>0
x is positive. Now if Y is positive then

y<7x/2

also y can be any negative value to satisfy this equation. Hence, Insufficient.

b) -y<x
here x is positive.

Now this is possible for any positive value of y.
If y is negative then for a value such that |y|<|x|, this statement will be true. Hence, Insufficient.

Taking both the statements together
y could still be positive or negative.

Hence answer is E.

It would be great in case someone could confirm my reasoning.

everything here works, yes.
i think tim (above) didn't understand that you were using |y| < |x| as a way to generate a case, rather than as something that *has* to be true.

also note that there's some initial confusion about the direction of the inequality sign in the original problem. it appears that the original has been edited -- because, in the second post (where the original is quoted), the inequality suddenly faces the other way.

[tim]

ah yes, thanks Ron. i misread the post..