If x < 0, Is y > 0 ?
1) x/y < 0
2) y-x > 0
Well, we know x is negative from the question itself, and we're asked if y is positive. So we'll need some relationship between x and y that helps us determine y's signage.
Statement one says that the quotient of x/y will be negative. This can only happen when a positive number and a negative number are the terms. We already know x is negative, therefore y must be the positive term. This statement alone is sufficient.
Statement two can be rewritten y > x, but this leaves open the possibilities that y is a greater negative number than x ( -1 > -2) or that y is zero or that y is positive. So this statement is insufficient.
The correct answer is A