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:

40 years

3 years ago, The average of the husband, the wife and the child was 27 years .

So today the average of their ages is =  27 + 3 = 30 years.

Sum of the present age of husband , wife and child is = 30 × 3 = 90 years

5 years ago,  The average of the wife and the child was 20 years.

So today the average of their ages is 20 + 5 = 25 years.

 Sum of the ages of wife and child = 25 × 2 = 50 years 

The husband’s age, now =  90–40  =  40 years.