The average monthly expenditure of a family was Rs.

Solution

First 4 months: Average expenditure = Rs. 2,500 Total for 4 months = 4 × 2500 = 10,000 Next 5 months: Average expenditure = Rs. 2,750 Total for 5 months = 5 × 2750 = 13,750 Last 3 months: Average expenditure = Rs. 3,550 Total for 3 months = 3 × 3550 10,650 Add these to get the total annual expenditure: Total Expenditure = 10,000+13, 750+10,650 =34, 400 Given the total savings for the year is Rs. 5,500, we can find the total income by adding the savings to the total expenditure: Total Income = Total Expenditure + Total Savings Total Income =34, 400+ 5,500 = 39,900 Average monthly income =39900/12 =3325.