The selling price of a watch is Rs 966 and the profit percentage on this sale is 15%. If the same watch is sold for Rs 798 instead, what will be the percentage loss on this second sale?

Introduction / Context:
This question mixes both profit and loss on the same article but at two different selling prices. It tests knowledge of how to find the cost price from a given profit situation and then use that cost price to compute a loss in another situation. Such questions often appear in bank and management entrance examinations.

Given Data / Assumptions:
- Selling price for the first sale = Rs 966 with 15% profit. - Selling price for the second sale = Rs 798. - The cost price of the watch is the same in both cases. - No additional charges, tax, or discount are involved in the prices listed.

Concept / Approach:
We again use the core formulas of profit and loss:
selling price = cost price * (100 + profit percent) / 100 cost price = selling price * 100 / (100 + profit percent) loss = cost price - selling price loss percent = (loss / cost price) * 100 The key is to calculate cost price from the first scenario and then calculate loss percentage in the second scenario.

Step-by-Step Solution:
Step 1: Let cost price be C. Step 2: For 15% profit, 966 = C * 115 / 100. Step 3: So C = 966 * 100 / 115 = 840. Step 4: In the second sale, selling price S2 = Rs 798. Step 5: Loss = C - S2 = 840 - 798 = Rs 42. Step 6: Loss percent = 42 / 840 * 100 = 5%.

Verification / Alternative check:
We can cross check by finding what 5% of 840 is. Five percent of 840 is 840 * 5 / 100 = Rs 42, which exactly matches the loss. Also, selling price after a 5% loss should be 95% of cost, that is 840 * 95 / 100 = 798, which agrees with the second selling price. Hence the result is confirmed.

Why Other Options Are Wrong:
Option 8 corresponds to a larger loss than actually occurs and would give a selling price much smaller than 798. Options 7.21 and 6.26 are approximate values that might arise from rounding at intermediate steps or using 966 instead of cost price as the base, but they do not match the correct method where cost price is the reference.

Common Pitfalls:
Learners often try to compare 966 and 798 directly and compute a percentage on that difference, which is incorrect because profit or loss percentage is always calculated on cost price, not on the higher selling price. Another pitfall is forgetting to convert percentage gains to multipliers correctly when going from selling price back to cost price.

Final Answer:
The loss on selling the watch for Rs 798 is 5%.