Correct Answer - Option 1 : 3 years

**Given****∶**

8 years ago, the average age of Raj’s family of 5 members = 25 years.

Age difference in two children’s = 4 years

**Formula Used****∶**

Sum of the observation = Average × No. of observations

**Calculation****∶**

Total age of 5 members, 8 years ago = 5 × 25 = 125 years

Total age of 5 members now = 125 + (8 × 5) = 125 + 40 = 165 years

Total age of 7 members now = 25 × 7 = 175 years

Sum of the ages of 2 children = 175 – 165 = 10 years

Let the age of the younger child be x years

Then age of elder child = (x + 4) years

So, x + x + 4 = 10

⇒ 2x = 10 – 4 = 6

⇒ x = 3 years

**∴ The present age of youngest child is 3 years.**