Practice Questions
Concept Explanation
Income-expenditure problems relate earning, spending, and savings through percentages. Savings = Income − Expenditure.
Basic Relation
If a person saves 20% of income, expenditure is 80% of income.
Change in Income or Expenditure
When income rises by a% and expenditure by b%, new savings = new income − new expenditure.
Equal Percent Trick
If income and expenditure both increase by the same percentage, savings also increase by that same percentage.
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Q1 EasyA person spends 70% of his salary. What percentage of his salary does he save?ExplanationIf expenditure is 70% of salary, savings = 100% − 70% = 30% of salary.
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Q2 EasyA person earns Rs. 20,000 per month and saves 25% of his income. What is his monthly expenditure?ExplanationExpenditure = 75% of Rs. 20,000 = Rs. 15,000.
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Q3 EasyIf monthly income is Rs. 30,000 and monthly expenditure is Rs. 24,000, what percentage of the income is saved?ExplanationSavings = Rs. 6,000. Percentage saved = (6000/30,000) × 100 = 20%.
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Q4 EasyA man spends 70% of his income. If his monthly income is Rs. 18,000, what are his monthly savings?ExplanationSavings = 30% of Rs. 18,000 = Rs. 5,400.
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Q5 EasyIf expenditure is 80% of income and the monthly income is Rs. 40,000, what is the monthly savings?ExplanationSavings = 20% of Rs. 40,000 = Rs. 8,000.
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Q6 MediumA man spends 75% of his income. His income increases by 20% and his expenditure also increases by 10%. Find the percentage increase in his savings.ExplanationLet income = 100. Expenditure = 75, savings = 25. New income = 120, new expenditure = 82.5, new savings = 37.5. Increase = (12.5/25) × 100 = 50%.
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Q7 MediumA man spends 75% of his income. His income increased by 20% and he increased his expenditure by 15%. His savings will then be increased by:ExplanationLet income = Rs. 100. Expenditure = Rs. 75, savings = Rs. 25. New income = Rs. 120, new expenditure = Rs. 86.25, new savings = Rs. 33.75. Increase = (8.75/25) × 100 = 35%.
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Q8 MediumMonthly income of Tony was Rs. 10,500 and his monthly expenditure was Rs. 8,000. Next month, his income increased by 20% and his expenditure increased by 25%. Find the percentage increase in his savings with respect to the previous month.ExplanationInitial savings = Rs. 2,500. New income = Rs. 12,600, new expenditure = Rs. 10,000, new savings = Rs. 2,600. Increase = (100/2500) × 100 = 4%.
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Q9 MediumIf savings are 15% of income and the monthly income is Rs. 24,000, what is the monthly expenditure?ExplanationExpenditure = 85% of Rs. 24,000 = Rs. 20,400.
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Q10 MediumIf monthly income is Rs. 36,000 and Rs. 27,000 is spent, what percentage of the income is saved?ExplanationSavings = Rs. 9,000. Percentage saved = (9000/36,000) × 100 = 25%.
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Q11 HardA man spends 75% of his income, if his income increases by 28% and his expenditure increases by 20%, then what is the increase or decrease percentage in his savings?ExplanationTake income 400, expenditure 300, savings 100. New income = 512, new expenditure = 360, new savings = 152. Increase = (52/100) × 100 = 52%.
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Q12 HardA, B and C spend 80%, 85% and 75% of their incomes, respectively. If their savings are in the ratio 8 : 9 : 20 and the difference between the incomes of A and C is Rs. 18,000, then the income of B is:ExplanationSavings ratios give incomes 40 : 60 : 80. Income of C − income of A = 40 units = 18,000 → 1 unit = 450. Income of B = 60 × 450 = Rs. 27,000.
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Q13 HardIncome rises by 25% while expenditure rises by 20%. If the original income and expenditure were Rs. 32,000 and Rs. 24,000 respectively, what are the new savings?ExplanationNew income = Rs. 40,000. New expenditure = Rs. 28,800. New savings = Rs. 11,200.
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Q14 HardMonthly income is Rs. 10,000 and monthly expenditure is Rs. 8,000. If income increases by 25% and expenditure increases by 10%, what are the new savings?ExplanationNew income = Rs. 12,500. New expenditure = Rs. 8,800. New savings = Rs. 3,700.
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DS1 Easy
What is the monthly expenditure of the person?
Statement IThe monthly income of the person is Rs. 20,000.
Statement IIThe person saves 25% of his monthly income.
ExplanationExpenditure = 75% of Rs. 20,000 = Rs. 15,000. Both income and savings percentage are needed. -
DS2 Easy
What percentage of income is saved each month?
Statement IThe monthly income of the person is Rs. 30,000.
Statement IIThe monthly expenditure of the person is Rs. 24,000.
ExplanationSavings = Rs. 6,000. Percentage saved = (6000/30,000) × 100 = 20%. Both income and expenditure are needed.
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DS3 Medium
What are the new savings after the increase?
Statement IThe income rises by 20% from Rs. 25,000.
Statement IIThe expenditure rises by 10% from Rs. 20,000.
ExplanationNew income = Rs. 30,000 and new expenditure = Rs. 22,000, so new savings = Rs. 8,000. Both statements are needed. -
DS4 Medium
Is the new savings amount more than Rs. 10,000?
Statement IThe new income is Rs. 40,000 after a 25% increase on Rs. 32,000.
Statement IIThe new expenditure is Rs. 28,800 after a 20% increase on Rs. 24,000.
ExplanationNew savings = Rs. 40,000 − Rs. 28,800 = Rs. 11,200, which is more than Rs. 10,000. Both statements are needed.