Difficulty: Easy
Correct Answer: 198
Explanation:
Introduction / Context:
This is a simple direct application of profit percentage. Once cost price and profit percent are known, the actual profit amount can be obtained easily. Such questions appear frequently to check whether you know and can quickly apply the basic percentage formula involving cost price and profit.
Given Data / Assumptions:
Concept / Approach:
The formula for profit amount when cost price and profit percent are known is: Profit = CP * profit_percent / 100. Selling price is then CP + Profit if required. In this question we only need the profit amount, so a single multiplication is enough.
Step-by-Step Solution:
Cost price CP = Rs 495.Profit percentage = 40%.Profit amount = CP * profit_percent / 100.Profit = 495 * 40 / 100.Profit = 495 * 0.40 = Rs 198.Therefore the shopkeeper earns a profit of Rs 198 on the calculator.
Verification / Alternative check:
If we want to verify, we can find the selling price as well. Selling price SP = CP + Profit = 495 + 198 = Rs 693. Now profit percentage = (SP - CP) / CP * 100 = (693 - 495) / 495 * 100 = 198 / 495 * 100 = 40%, which matches the given profit percentage and confirms that the profit amount of Rs 198 is correct.
Why Other Options Are Wrong:
Values like Rs 186, Rs 218 or Rs 226, when added to 495, would give selling prices that correspond to profit percentages different from 40%. For example, 186 / 495 * 100 is less than 40%, and 226 / 495 * 100 is more than 40%. Only Rs 198 yields exactly 40% profit on Rs 495.
Common Pitfalls:
Students sometimes confuse profit percentage with the percentage of the selling price instead of the cost price. Others might mistakenly compute 495 * 0.04 or make arithmetic errors in multiplication. Writing the formula clearly and handling the decimal multiplication carefully reduces the chance of mistakes.
Final Answer:
The profit earned on the calculator is Rs 198.
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