The sum of the ages of 5 members comprising a family, 3 years ago was 80 years. The average age of the family today is the same as it was 3 years ago, because of an addition of a baby during the intervening period. How old is the baby?
Answer & explanation
Answer: (b) 1 year
The five members now total 80 + 15 = 95 years. With the baby, six people must total 6 × 16 = 96 years to keep the average at 16, so the baby is 1 year old.
- Three years ago: 5 members, total 80, average 16.
- Today the same 5 total 80 + 5 × 3 = 95.
- Today 6 members average 16: total 6 × 16 = 96.
- Baby's age = 96 − 95 = 1 year.
Remember · Age totals grow by (number of people × years passed); compare the required total with the grown total.
Question and answer: UPSC's official GS Paper II (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·