Correct Answer - Option 3 : 27 years
GIVEN:
Average age of 5 members = 39 years
Average age after marriage = 42 years
FORMULA USED:
Average = Sum of observations/Total number of observations
CALCULATION:
Sum of ages of 5 members = 39 × 5 = 195 years
Remaining members after marriage = 4
Sum of ages of 4 members = 42 × 4 = 168 years
Age of the girl = 195 - 168 = 27 years
∴ The age of the girl is 27 years
ALTERNATE SOLUTION:
Average difference = 42 - 39 = 3 years
Total difference = 3 × 4 = 12 years
Age of girl = 39 - 12 = 27 years
∴ The age of the girl is 27 years