It costs ₹ 1 to photocopy a sheet of paper. However, 2% discount is allowed on all photocopies done after first 1000 sheets. How much will it cost to copy 5000 sheets of paper?

### Concept & Logic This is a tiered pricing problem. The total cost is split into two distinct segments: a fixed cost for the initial threshold and a discounted cost for the remainder. $$ \text{Total Cost} = (\text{Initial Sheets} \times \text{Base Price}) + (\text{Remaining Sheets} \times \text{Discounted Price}) $$ ### Step-by-Step Solution * **Given**: * Total sheets to copy = 5000 * Cost per sheet for first 1000 sheets = ₹ 1 * Discount on sheets after 1000 = $2\%$ * **Deduction**: * Discounted price per sheet = $1 - (2\% \text{ of } 1) = 1 - 0.02 = \text{₹ } 0.98$ * Number of sheets at discounted price = $5000 - 1000 = 4000$ sheets * **Calculation**: * Cost of first 1000 sheets = $1000 \times 1 = \text{₹ } 1000$ * Cost of remaining 4000 sheets = $4000 \times 0.98$ * $4000 \times 0.98 = 40 \times 98 = 3920$ * Total Cost = $1000 + 3920 = \text{₹ } 4920$ ### Exam Strategy & Shortcut Instead of calculating the discounted unit price ($0.98$), calculate the total cost *without* any discount first, then simply subtract the total discount value. Total cost without discount = $5000 \times 1 = 5000$. The discount is $2\%$ strictly on the extra 4000 sheets. Total discount amount = $2\%$ of $4000 = 80$. Final Cost = $5000 - 80 = 4920$. This method completely bypasses decimal multiplication. ### Common Pitfall A very frequent error is applying the $2\%$ discount to the entire bulk order of 5000 sheets. This leads to calculating $5000 \times 0.98 = 4900$, which is placed as a trap option (option c). Always respect the "after first 1000" condition. ### Final Answer **Therefore, the correct answer is ₹ 4920.**