Correct Answer - Option 4 : 2 years
Given:
Two years ago, the average age of a family of 8 members was 18 years
Formula used:
Average = sum of the observation/number of observation
Calculation:
2 year ago,
Average age of family = (2 × 8)/8
⇒ Average age of family 2 year age = 2
So, the average age of family = 18 + 2 = 20
According to the question,
After the born of baby, the average age of family is same today
So, number of family member is 9
Let the new born baby age be P years
⇒ 18 = [(20 × 8) + P]/9
⇒ 162 = 160 + P
⇒ P = 2
∴The age of the baby 2 years.
