If three years ago the average age of a family of 6 members was 19 years. A baby having been born, the average age of the family now remains the same.The age or baby in years is

The correct answer is (b).

The total age of the family three years ago was $6 \times 19 = 114$ years. The total age of the family now is $114 + 3 \times 6 = 126$ years. The total age of the family including the baby is $126 + 1 = 127$ years. The baby is 1 year old.

Option (a) is incorrect because 11/2 is not an integer.

Option (c) is incorrect because 2 is not an integer.

Option (d) is incorrect because the baby is 1 year old.