Maths question from JKP Constable exam, 2024 by JKSSB
In a family, the average age of a father and a mother is 35 years. The average age of the father, mother and their only son is 27 years. What is the age of the son?
Last updated Jun 24, 2026
Correct Answer:
Option B —
10.5 years
Let the father's age = F years
Let the mother's age = M years
Let the son's age = S years
Average age of father and mother is 35 years:
(F + M) / 2 = 35
⇒ F + M = 70 years
Average age of father, mother and son is 27 years:
(F + M + S) / 3 = 27
⇒ F + M + S = 81 years
Substitute the value from step 1 into step 2:
70 + S = 81
⇒ S = 81 - 70
⇒ S = 11 years
Wait — correction in final calculation: 81 - 70 = 11.
So the son's age is 11 years.
Correct answer: C) 11 Years
(The slight miscalculation earlier was due to hasty arithmetic; 81 - 70 is clearly 11.)
This is a standard average problem using the total sum approach. The parents together are 70 years old on average, and adding the son pulls the three-person average down to 27, so the son must be younger than 27 by an amount that balances the equation.
Answer verified by Quintessence Classes faculty — Karan Nagar, Srinagar.
