In 10 years, A will be twice as old as B was 10 years ago. If A is now 7 years older than B the present age of B is  Choose the correct choice from the following answers
A) 37	B) 38	C) 39	D) 40	E) 41

Rationale: "let present age of a be a and b be b a + 10 = 2 * ( b - 10 ) = > 2 b - a = 30 . . . . . . ( i ) a = b + 7 = > 2 b - b - 7 = 30 b = 37 so the present age of b is 37 years answer : a"
Answer: A