DS question from GMATprep!

Is the answer C?

1) 2x-2y = 1
x-y = 1/2
Possible values are: x = 0, y=-1/2
x=1, y=1/2
So, we can't say.
2) x/y > 1
x>y
- Can't say

Combining 1 & 2
- x and y are positive.

Jay,

from x-y= 1/2, x could be -4.5 and y could be -5 and x-y would still equal 1/2. I am not sure if your logic for (1) is right

you are right. The answer has to be E. right?

owodee wrote:Are x and y both positive?

(1) 2x - 2y = 1

(2) x/y > 1

OA after a few replies

Is it C ?

1 - insufficient. Multiple values of x and y satisfy x-y = 1/2

2 - insufficient. x and y can be either both positive or both negative.

Together,

x - y = 1/2
Dividing both sides by y

x/y - 1 = 1/2y

We know x/y > 1 and so left side of the eqn is positive. This implies
1/2y is positive and so y is positive.

If x/y > 1 and y is positive, then x has to be positive.

So C ?

Wow, thanks a lot jayhawk, I dont think I would have thought of that.

The answer OA is C.