If an electricity bill is paid before due date, one gets a reduction of $4\%$ on the amount of the bill. By paying the bill before due date a person got a reduction of ₹ $13$. The amount of his electricity bill was

### Concept & Logic This problem equates a percentage value directly to an absolute currency value. The reduction percentage corresponds exactly to the reduction amount. ### Step-by-Step Solution **Given:** * Discount percentage = $4\%$ * Discount amount = ₹ $13$ **Calculation:** * Let the total amount of the electricity bill be $x$. * The reduction is $4\%$ of the total bill, which equals $13$. $$4\% \text{ of } x = 13$$ $$\frac{4}{100} \times x = 13$$ * Solve for $x$: $$x = \frac{13 \times 100}{4}$$ * Simplify the fraction: $$x = 13 \times 25$$ * Calculate the final product: $$x = 325$$ ### Exam Strategy & Shortcut If $4\%$ equals $13$, you need to find $100\%$ (the full bill). Notice that $4 \times 25 = 100$. Simply multiply the reduction amount by $25$ to find the total bill. $13 \times 25 = 325$. This mental math shortcut avoids setting up an algebraic equation entirely! ### Common Pitfall A potential mistake is subtracting the ₹ $13$ from the final calculated amount, confusing the original bill amount with the final paid amount. The question explicitly asks for "The amount of his electricity bill" (the original amount), not the discounted amount paid. ### Final Answer **Therefore, the correct answer is ₹ 325.**