Rahul is 30 years older than his daughter Mary. In 20 years Rahul will be twice as old as Mary. What is Mary current age.	Choose the correct answer:
A) 12 B) 14 C) 10 D) 16 E) 18

Rationale: now : mary = x , rahul = x + 30 in 20 years mary = x + 20 , rahul = x + 30 + 20 or 2 ( x + 20 ) x + 30 + 20 = 2 ( x + 20 ) x + 50 = 2 x + 40 50 - 40 = 2 x - x x = 10 mary is 10 years old answer : c
Answer: C