Three years back the average age of a family of 6 members was 19 years. A baby having being born, the average of the family remains the same. Then the age of the baby (in years) is

The correct answer is (c) 2.

Three years ago, the total age of the family was 6 x 19 = 114 years.
The total age of the family now is 114 + 3 x 6 = 132 years.
The total age of the family including the baby is 132 + 2 = 134 years.
The baby is 2 years old.

Option (a) is incorrect because 1 year is too young for a baby.
Option (b) is incorrect because 11/2 years is not an integer.
Option (d) is incorrect because 3 years is too old for a baby.