if a father said to his elder son , ` ` i was as old as you are at the present at the time of your birth ' ' . if the father ' s age is 25 years now , what was the son ' s age 4 years back ? Choose the correct answer:	A) 7.5	B) 8.5	C) 9	D) 9.5	E) 10

Rationale: let son ' s present age be a years . then , ( 25 − a ) = a ⇒ 2 a = 25 ⇒ a = 25 / 2 = 12.5 son ' s age 4 years back = 12.5 - 4 = 8.5 answer : b
Answer: B