Question

Five years ago the average age of husband and wife was 23 years. Today the average age of husband, wife and child is 20 years. How old is child?

Answer 1

Step-by-step explanation:

average present age of husband & wife = (23 + 5)/2 years

Present total age of husband & wife = (2*23 + 2*5) = 56 years

average present age of   husband, wife & child = 20/3 years

Present total age of husband, wife & child = (3*20) = 60 years  

Present age of the child = (60 - 56) years = 4 years