The average age of a family of 10 members is 20 years. If the age of the youngest member of the family is 10 years, then the average age of the members of the family just before the birth of the youngest member was approximately.

A. 27.14 years

B. 12.5 years

C. 14.28 years

D. $$11\frac{1}{9}$$ years

Answer: Option D

Solution(By Examveda Team)

According to the question,
Average age of a family of 10 members is = 20 years
Sum of the age of 10 members = 20 × 10 = 200 years
If the age of youngest member is = 10 years
Sum of the age of 9 members at the time of birth of youngest member
= 200 - 10 × 10
= 200 - 100
= 100 years
∴ Average age of 9 members is
$$\eqalign{ & = \frac{{100}}{9} \cr & = 11\frac{1}{9}{\text{ years}} \cr} $$