A is two years older than B who is twice as old as C. The total of the ages of A, B and C is 27. How old is B? Pick one
A) 25 B) 20 C) 15 D) 10 E) 5

Rationale: "let age of c = x . then , age of b = 2 x age of a = 2 + 2 x total age of a , b and c = 27 ⇒ ( 2 + 2 x ) + 2 x + x = 27 ⇒ 5 x = 25 ⇒ x = 255 = 5 b ' s age = 2 x = 2 × 5 = 10 answer is d ."
Answer: D