I had just enough money to buy a watch at list price P. With a 25% discount I could also buy another watch worth Rs 940 for my sister. What price did I pay for my own watch?

Introduction:
“Just sufficient” for the list price means the amount of money equals the marked price. With a 25% discount, the saving is 25% of P, which exactly funds a second watch priced at Rs 940. We back out P from this relation and then compute the paid price (75% of P).

Given Data / Assumptions:

• Total money M = P (the list price of my watch)
• Discount = 25% ⇒ paid price = 0.75P
• Leftover = P − 0.75P = 0.25P = Rs 940

Concept / Approach:
Set 0.25P = 940 to get P. Then find the actual amount paid for the first watch as 0.75P.

Step-by-Step Solution:
0.25P = 940 ⇒ P = 940 * 4 = 3760Amount paid for my watch = 0.75 * 3760 = Rs 2820

Verification / Alternative check:
Money M = 3760; after paying 2820, remaining = 940, matching the second watch price.

Why Other Options Are Wrong:
2700/1800 underestimate 75% of 3760; 3760 is the list price, not the amount paid.

Common Pitfalls:
Confusing “price paid” with list price; applying 25% to 940 instead of to P.

Final Answer:
Rs. 2820