Five years ago, the average age of Mr and Mrs Kulkarni and their two children was 26 years. A baby has been born since then, and today the average age of all five family members is 25.2 years. How old is the baby?

Explanation

1. 01

   Five years ago the four members' ages totalled $4 \times 26 = 104$ years.

2. 02

   Each of the four is now 5 years older: $104 + 4 \times 5 = 124$ years.

3. 03

   Today's total for five members = $5 \times 25.2 = 126$ years.

4. 04

   Baby = $126 - 124 = 2$ years.