The sum of the present age of a father and a son is 60 years. Five years before, the age of the father was four times that of son. What is the present age of the son ?

• A. 18 years
• B. 15 years
• C. 21 years
• D. 25 years

Answer: (B)

Let the father's age be x and son's age yTherefore, x + y = 60   ....................(i)Five years back, (x - 5) = 4 (y - 5)x - 4y = - 15 ......................(2)Solving (1) and (2), x = 45 and y = 15