Question

The average monthly expenditure of a family for the first four months is Rs. 2750, for the next three months is Rs. 2940, and for the last five months Rs. 3130. If the family saves Rs. 5330 throughout year, find the average monthly income of the family for that year.

• A. Rs. 3800
• B. Rs. 3500
• C. Rs. 3400
• D. Rs. 4200
• E. None of these

Answer 1

The correct option is C Rs. 3400

Average monthly expenditure of 4 months = Rs. 2700
Total expenditure for 4 months = $Rs.2700\times 4=Rs.11000$
Average monthly expenditure of 3 months = Rs. 2940
Total expenditure for 3 months = $Rs.2940\times 5=Rs.8820$ ....(1)
Average monthly expenditure of 5 months = Rs. 3130
Total expenditure of 5 months = Rs. 31020
= Rs. 1560 ....(2)
Total expenditure in the whole year
= Rs. 11000 + 8820 + Rs. 15650
= Rs. 35470
Savings during the whole year = Rs. 5330
Total income of the family during the year
= Rs. 35470 + Rs. 5330 = Rs. 40800
$\therefore$ Average monthly income during the year
$\frac{40800}{12}=Rs.3400$