A manâ€™s current age is (2/5) of the age of his father. After 10 years, he will be (1/2) of the age of his father. What is the age of father at now?
Pick:
A) 40  B) 45  C) 38  D) 50  E) 39

Rationale: "let , father â € ™ s current age is a years . then , man â € ™ s current age = [ ( 2 / 5 ) a ] years . therefore , [ ( 2 / 5 ) a + 10 ] = ( 1 / 2 ) ( a + 10 ) 2 ( 2 a + 50 ) = 5 ( a + 10 ) a = 50 d"
Answer: D