Given : x and y are positive integers. I. Given : 20 < x It says nothing about y. ∴ I alone is not sufficient. II. Given : y > 17 It says nothing about x. ∴ II alone is not sufficient. I & II. x > 20, and y > 17 For y = 18, 19 and 20, y < x. But for x, y > 21, we can’t say definitely which one is greater. e.g. x = 22 and y = 25, y > x. ∴ I & II together are not sufficient.