SSC CHSL Model Paper 10

Let the present ages of son and father be x and (60 – x) years respectively.
Then, (60 – x) – 6 = 5(x – 6)
⇒ 54 – x = 5x – 30
⇒ 6x = 84
⇒ x = 14
⇒ Son's age after 6 years = (x + 6) = 20 years