Question 615717
let the present age of john be x
so the age of jamie this year will be 3x

next year age of john will be = x+1
  and  age of jamie will be 3x+1

given Next year she will be twice as old as john.

  so, 3x+1 = 2(x+1)

   => 3x +1 = 2x+2
   => x=1 and 3x will be = 3
             
so, age of jamie is 3 years.

Ans: 3 years