Mohanlal purchased a TV set for ₹ 12500 and spent ₹ 300 on transportation and ₹ 800 on installation. At what price should he sell it so as to earn an overall profit of 15%? (Specialist Officers, 2009)

### Concept & Effective Cost Price Overhead expenses such as transportation, repairs, and installation must be added to the initial purchase price to determine the true, effective Cost Price (CP). Profit is always calculated on this effective CP. $$ \text{Effective CP} = \text{Purchase Price} + \text{Overhead Expenses} $$ ### Step-by-Step Solution Given: * Purchase Price of TV = ₹ 12500 * Transportation Cost = ₹ 300 * Installation Cost = ₹ 800 * Desired Profit = 15% Calculation: 1. Find the total effective Cost Price by adding all expenses. $$ \text{Effective CP} = 12500 + 300 + 800 = 13600 $$ 2. Calculate the required selling price to achieve a 15% profit. $$ \text{SP} = \text{Effective CP} \times \left(1 + \frac{15}{100}\right) $$ $$ \text{SP} = 13600 \times 1.15 $$ 3. Break the calculation down for simplicity: calculate 10% and 5% of 13600. $$ 10\% \text{ of } 13600 = 1360 $$ $$ 5\% \text{ of } 13600 = 680 $$ 4. Add the profit to the effective CP. $$ \text{Total Profit} = 1360 + 680 = 2040 $$ $$ \text{SP} = 13600 + 2040 = 15640 $$ Since ₹ 15640 is not among the given options (a, b, c, or d), the correct choice is "None of these". ### Exam Strategy & Shortcut Use the Unit Digit trick to verify options quickly. $136 \times 115$. The last significant digit of $6 \times 5$ is 0. Move to the next digit: $(6 \times 1) + (3 \times 5) = 6 + 15 = 21$. So the tens digit before the zeros is a 4 (because $13600 \times 15\% \rightarrow 136 \times 15 = 2040$). $13600 + 2040 = 15640$. You can quickly see none of the specific numerical options match. ### Common Pitfall Forgetting to include the overhead expenses in the cost price and calculating the 15% profit purely on the ₹ 12500 purchase price ($12500 \times 1.15 = 14375$), which is intentionally provided as distractor option (a). ### Final Answer Therefore, the correct answer is **(e) None of these**.