Question

The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is:

Answer 1

Let the present age of Husband,wife and child be A, B , C respectively.

Age of each 3 years back = A-3 , B-3, C-3

Average= $\frac{Sum of observation}{Number of observation}$

#We can make an equation from the first part of information,

(A-3)+(B-3)+(C-3)/ 3 =27

A+B+C-9=81

A+B+C = 90.........................................................(1)

Age of wife 5 years ago = B-5
Age of child 5 years ago = C-5 

Average of their ages,

(B-5)+(C-5)/2 = 20
B+C -10 =40
B+C =50.................. (2)

Putting .....(2) in ...(1)

from .(1) We know,

A+B+C =90

We know from .(2) , B+C =50

A+B+C=90
A+50=90
A=90-50=40

A=Present age of father, Thats the value we require

Age of father is 40 years.