In 10 years, A will be twice as old5as B was 10 years ago. If A is now 12 years older than B, the present age of B is Choose the correct answer:
A) 35 B) 37 C) 39 D) 41 E) 42

Rationale: "explanation : let b ' s age = x years . then , as age = ( x + 12 ) years . ( x + 12 + 10 ) = 2 ( x — 10 ) hence x = 42 . present age of b = 42 years answer : option e"
Answer: E