Question

The average age of a family of 5 members is 39 years. If one female member of the family got married and moved away with her husband the new average age of the family becomes 42 years, Then find the age of the girl who got married.
1. 26 years
2. 25 years
3. 27 years
4. 28 years

Answer 1

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