3.0 years
2.5 years
2.0 years
1.2 years
Answer is Wrong!
Answer is Right!
The correct answer is (a) 3.0 years.
Four years ago, the total age of the family was $4 \times 18 = 72$ years. Today, the total age of the family is $72 + 4 \times 1 = 76$ years. The age of the baby is $76 – 4 \times 18 = 3$ years.
Option (b) is incorrect because $2.5$ years is less than the age of the baby.
Option (c) is incorrect because $2$ years is less than the age of the baby.
Option (d) is incorrect because $1.2$ years is less than the age of the baby.