The difference between the ages of two persons is 20 years. Fifteen years ago, the elder one was twice as old as the younger one. The present age of the younger person is? Choices:  A) 30  B) 35  C) 25  D) 28  E) 32

Rationale: let their ages be x years and ( x + 20 ) years then , ( x + 20 ) - 15 = 2 ( x - 15 ) x + 5 = 2 x - 30 x = 35 answer is b
Answer: B