A man is 24 years older than his son. In three years, his age will be twice the age of his son. The present age of the son is Choose the correct choice from the following answers:  A) 14 years  B) 18 years  C) 20 years  D) 21 years  E) none

Rationale: "solution let the son ' s present age be x years . then , man ' s present age = ( x + 24 ) years . then â € ¹ = â € º ( x + 24 ) + 3 = 2 ( x + 3 ) â € ¹ = â € º x + 27 = 2 x + 6 x = 21 . answer d"
Answer: D