In 10 years,A will be twice as old as B was 10 years ago.If A is now 9 years older than B,the present age of B is :  Choose the most appropriate option:
A) 19 Years B) 29 Years C) 39 Years D) 49 Years E) 59 Years
Solution   Let B's present age = x years.Then,A's present age =(x +9) years.   ∴ (x + 9)+ 10 = 2 (x - 10) ⇔ x + 19 = 2x- 20 ⇔ x = 39.Answer 39 Years
<result>C</result>
In 10 years,A will be twice as old as B was 10 years ago.If A is now 9 years older than B,the present age of B is :