Correct Answer - Option 4 : 3 years
Given:
The average age of the 3 members of the family 3 years ago = 32 years
The average age of the family (i.e. 4 members) today = 27 years
Formula used:
Sum of all observations = Average × Total number of observations
Calculation:
Total age of family (i.e. 3 members) 3 years ago = 32 × 3 = 96 years
Total age of 3 members today = 96 + 3 × 3 = 105
Total age of family (i.e. 4 members) today = 27 × 4 = 108
Total age of child today = 108 - 105 = 3 years
∴ Age of child is 3 years