Gmatprep

The question here is whether x - y > x + y, which is equivalent to -y > y (I subtracted x from each side). This is the case only when y is negative. Let me give you a few examples:
a. if y = 10, then -y = -10, which is smaller than 10 and therefore does not fit the description
b. if y = -5, then -y = -(-5) = 5, which is indeed greater than -5 and fits the initial restriction.

Now, let's analyze each stmt:
1. x = 8, but x - y > 10 means that 8 - y > 10 or that -y > 2 or that y < -2. This is consistent with our conclusion that y is negative, so 1 is sufficient.
2. y is negative, which is consistent with our conclusion.

So the correct answer is D