Answered

A 42 year old man has a son 12 years old. In how many years will the father be twice as old as his son. 

Sagot :

Cheahjimmyviz
let x = number of years when the father is twice as old as his son
thus
         42 + x = 2(12+x)
          x =  42-24 =18
   in 18 years time