Question

3 years ago, the average age of a family of 5 members was 17 years. A baby having been born, the average age of the family is same today. The present age of the baby is 

(a) 3 years 

(b) 2 years 

(c) 1\(\frac12\)years 

(d) 1 year

Answer 1

Answer is: (b) 2 years.

Total age of the family three years ago = 17 × 5 = 85 years. 

Let the present age of the child be x years. 

Present total age of the family = 85 + 5 × 3 + x = (100 + x) years.

Given \(\frac{100+x}{6}=17\)

⇒ 100 + x = 102 ⇒ x = 2 years.