Question

Which expression results in a rational number?
(1) Root 121- Root 21
(2) Root 25 x Root 50
(3) Root 36 / Root 225
(4) 3 Root 5 + 2 Root 5

Answer 1

3 because the root of 36 is 6 and the root of 225 is 15. Hope this clarifies. For 2, the root of 25 is 5, but 50 is not a perfect square.