If x and y are integers such that x^2= 2y and xy = 256, then x – y = ?
Pick one
A) - 30	B) - 24	C) - 5	D) 5	E) 20

Rationale: "here x and y are integers . x ^ 2 = 2 y , xy = 256 . substitute ( x ^ 2 ) / 2 = y in xy = > x ^ 3 = 256 * 2 = > x ^ 3 = 512 . here x ^ 3 is positive , x is also positive . x = 8 then y = 32 . x - y = - 24 so option b is correct"
Answer: B