Question

The mean age of 5 children of a family is 12 years. If four of them are respectively 6,11,13 and 16 years. Find the age of fifth child.

Answer 1

let the age of fifth child be 'x'
Mean/average=sum of observations /total observations
Therefore 6+11+13+16+x/5=12
12*5=60
60=6+11+13+16+x
60=46+x
Hence x=14
So age of fifth child is 14 years
Hope this will help.

Answer 2

let x by the fifth age
6+11+13+16+x÷5=12
=46+x÷5=12
=46+x=12×5
=46+x=60
=x=60-46
x=14