Question 434074
  ANSWER:
  father's present age is :   63
  john's present age is   :   26


  add 63 and 26 and the result is  89.


  add 11 years to john's age : 26 + 11  = 37
  add 11 years to Father's age : 63 + 11 = 74


  multipLy the age of John after 11 years by 2     :  37 x 2 = 74


  so his father's age is twice the age of John after 11 years. ^_^