3 years ago the average 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:

Let age of the baby is x.
3 years ago total age of the family = 5 × 17 = 85 years
Total age of the 5 member at present time = 85 + 3 × 5 = 100 years
Total age of the family at present time including baby,
= 100 + X
The average of the family including baby at present time,
= 17 years
$$\frac{{100 + {\text{x}}}}{6} = 17$$
100 + X = 102
X = 102 - 100 = 2 years