The ages of two person differ by 20 years. If 10 years ago, the elder one be 5 times as old as the younger one, their present ages(in years) are respectively  Choose the correct choice from the following answers:
A) 30 , 10  B) 25 , 5  C) 29 , 9  D) 35 , 15  E) 20,10

Rationale: "let their ages be x and ( x + 20 ) years . then , 5 ( x - 10 ) = ( x + 20 - 10 ) = > 4 x = 60 = > x = 15 their present ages are 35 years and 15 year . answer : d"
Answer: D