Correct Answer - Option 3 : 37 years
Given:
Average age of 4 brothers = 12 years
Average age after age of mother is included = (12 + 5) years
⇒ 17 years
Formula used:
Sum of ages = Average age × Number of persons
Calculation:
Sum of ages of 4 brothers = 12 × 4 years
⇒ 48 years
Sum of ages of 4 brothers and mother = 17 × 5 years
⇒ 85 years
Age of mother = (85 – 48) years
⇒ 37 years
∴ The age of mother is 37 years