Marked price, usual profit, and seasonal discount — find new gain A shopkeeper sells an umbrella for ₹30 and gains 20% (usual sale). During a clearance sale, he offers a 10% discount on the marked price. What is his gain percentage during the sale season?

Introduction / Context:
This question links a normal profit scenario with a later discount on the marked price. If the usual sale price equals the marked price, applying a discount reduces the selling price while the cost remains unchanged, leading to a different profit percentage.

Given Data / Assumptions:

• Usual SP (and marked price) = ₹30 with 20% profit.
• Hence CP = SP / 1.20.
• Discount during sale = 10% of marked price.

Concept / Approach:
First find the cost price from the usual sale. Then compute the discounted sale price (90% of ₹30). Finally, compute the profit percentage relative to CP during the sale.

Step-by-Step Solution:
CP = 30 / 1.20 = ₹25.Discounted SP = 30 * 0.90 = ₹27.Profit during sale = 27 − 25 = ₹2.Gain% = 2 / 25 * 100 = 8%.

Verification / Alternative check:
Forward check: Usual margin is ₹5 on ₹25 (20%). Applying a 10% discount from ₹30 to ₹27 reduces the margin to ₹2, which is 8% of ₹25.

Why Other Options Are Wrong:
7, 7.5, 9, and 6 do not match the exact CP- and discount-based computation.

Common Pitfalls:
Applying 10% to the CP or to the profit instead of to the marked price, or assuming the marked price changes between scenarios.

Final Answer:
8