While selling a watch, a shopkeeper gives discount of 5% on it's marked price. If he gives discount of 10%, then he earns 25 less as profit. Marked price of the watch is

Let the marked price be M. A 5% discount gives a selling price of 0.95M, and a 10% discount gives 0.90M. The cost price never changes, so the drop in profit equals the drop in selling price: 0.95M minus 0.90M = 0.05M = 25. That gives M = Rs.500, so C is correct.

Why the others fail when tested against the same condition:

• A (Rs.300): 5% of 300 is 15, so the profit gap would be 15, not 25.
• B (Rs.380): 5% of 380 is 19, not 25.
• D (Rs.700): 5% of 700 is 35, which overshoots.

The core concept is that the profit difference depends only on the marked price and the difference in discount rates, not on the cost price. This is the same logic used in retail margin and discount policy questions, where a few percentage points of markdown can wipe out a large share of profit.

Trap: aspirants often try to find the cost price or assume 25 is 5% of the cost price. The cost price is not given and is not needed. Only the 5% difference applies to the marked price.