A person's present age is two-fifth of the age of his mother. After 10years, he will be one - half of the age of his mother. How old is the mother at present ? Choose one
A) 25  B) 40  C) 32  D) 50  E) 28

Rationale: let the mother ' s present age be x years then the person ' s present age = 2 x / 5 ( 2 x / 5 ) + 10 = 1 / 2 ( x + 10 ) 2 ( 2 x + 50 ) = 5 ( x + 10 ) x = 50 answer is d
Answer: D