Manu earns Rs. per month and wants to save an average of Rs. per month in a year. In the first nine months, his monthly expense was Rs. , and he foresees that, tenth month onward, his monthly expense will increase to Rs. . In order to meet his yearly savings target, his monthly earnings, in rupees, from the tenth month onward should be
Manu earns Rs. per month and wants to save an average of Rs. per month in a year. In the first nine months, his monthly expense was Rs. , and he foresees that, tenth month onward, his monthly expense will increase to Rs. . In order to meet his yearly savings target, his monthly earnings, in rupees, from the tenth month onward should be
Solution
Manu wants to save an average of Rs. 550 per month over the entire year. This means:
Total yearly savings target = Rs. 550 × 12 months = Rs. 6600
Income for first 9 months:
Monthly income = Rs. 4000
Total income = Rs. 4000 × 9 = Rs. 36000
Expenses for first 9 months:
Monthly expense = Rs. 3500
Total expenses = Rs. 3500 × 9 = Rs. 31500
Savings achieved in first 9 months:
Savings = Income - Expenses
Savings = Rs. 36000 - Rs. 31500 = Rs. 4500
Since Manu has already saved Rs. 4500 in the first 9 months, he needs to save the remaining amount in the last 3 months.
Required savings for last 3 months:
Total target - Already saved = Rs. 6600 - Rs. 4500 = Rs. 2100
Expected expenses for last 3 months:
Monthly expense = Rs. 3700 (given that expenses increase)
Total expenses = Rs. 3700 × 3 = Rs. 11100
Required total income for last 3 months:
To achieve Rs. 2100 savings with Rs. 11100 expenses
Required income = Savings + Expenses = Rs. 2100 + Rs. 11100 = Rs. 13200
Monthly earnings needed from 10th month onward:
Rs. 13200 ÷ 3 months = Rs. 4400 per month
Therefore, Manu needs to earn Rs. 4400 per month from the tenth month onward to meet his yearly savings target.