In 10 years, A will be twice as old as B was 10 years ago. If A is now 4 years older than B the present age of B is
Choose the correct answer:
A) 37
B) 38
C) 39
D) 34
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 + 4 = > 2 b - b - 4 = 30 b = 34 so the present age of b is 34 years answer : d
Answer: D