A merchant marks an article at Rs 300 and allows a 25% discount. If he still gains 12.25%, find the cost price of the article.

Introduction:
This is a marked-price and discount problem culminating in a gain on cost. Convert the discount into the actual selling price and then relate it to cost via the gain percentage to solve for the cost price (CP).

Given Data / Assumptions:

• Marked Price (MP) = Rs 300
• Discount = 25% → Selling Price (SP) = 300 * (1 − 0.25) = Rs 225
• Gain% on cost = 12.25% (≈ 0.1225)

Concept / Approach:
SP = (1 + gain%) * CP. Substitute SP = 225 and gain% = 0.1225 to compute CP. Minor rounding is acceptable if the nearest standard option matches the implied CP closely.

Step-by-Step Solution:
225 = (1 + 0.1225) * CP = 1.1225 * CPCP = 225 / 1.1225 ≈ 200.44...Closest standard cost price in options = Rs 200

Verification / Alternative check:
If CP = 200, gain% = (225 − 200)/200 * 100 = 12.5%, which is within rounding proximity to 12.25% stated (typical exam rounding/typo scenario). Among listed options, Rs 200 is the intended choice.

Why Other Options Are Wrong:
220/240/260: Do not reconcile with SP = 225 and gain near 12%.

Common Pitfalls:
Applying discount on cost instead of marked price; computing gain on SP rather than CP.

Final Answer:
200