Difficulty: Easy
Correct Answer: Rs. 4000
Explanation:
Introduction / Context:This is a reverse calculation of income from given expenditure and savings rate. If savings are a fixed percentage of income, expenditure is the remainder. We use the complement of the saving rate to compute the income.Given Data / Assumptions:
Concept / Approach:If savings are 1/8 of income, then expenditure is 7/8 of income. So 7I/8 = 3,500 → I = 3,500 * 8 / 7. This avoids trial-and-error and yields an exact figure.Step-by-Step Solution:
Savings = (1/8)I, so expenditure = I − (1/8)I = (7/8)I.Given (7/8)I = 3500 ⇒ I = 3500 * 8 / 7.I = 3500 * 8 / 7 = 500 * 8 = Rs. 4,000.Verification / Alternative check:Savings at 12.5% of 4,000 = 500; expenditure = 4,000 − 500 = 3,500, matching the given data.
Why Other Options Are Wrong:
Common Pitfalls:Applying 12.5% on expenditure instead of income or mis-converting 12 1/2% to fraction.
Final Answer:
Rs. 4000
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