1.  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 the same today. The present age of the baby is :
A. 1 year
B. 1 year 6 months
C. 2 years
D. 3 years

Answer: Option C

Explanation:

Total age of 5 members, 3 years ago
          = (17 x 5) years = 85 years.

Total age of 5 members now = (85 + 3 x 5) years
                                          = 100 years

Total age of 6 members now = (17 x 6) years
                                          = 102 years.

 Age of the baby = (102 - 100) years = 2 years.