Rebate target: A merchant announces a 25% rebate on readymade garments. If a buyer wants a total rebate of ₹400, how many shirts priced at ₹320 each should he purchase?

Introduction / Context:
Here, the discount per unit is fixed as a percentage of the marked price. Knowing the target total rebate, compute how many units are needed to accumulate that saving.

Given Data / Assumptions:

• Unit price = ₹320
• Rebate = 25% of unit price
• Desired total rebate = ₹400

Concept / Approach:
Discount per shirt = 0.25 * 320. Number of shirts = total desired rebate / discount per shirt. Round only if the result is an integer requirement (it is exact here).

Step-by-Step Solution:
Discount per shirt = 0.25 * 320 = ₹80Number of shirts = 400 / 80 = 5

Verification / Alternative check:
Buying 5 shirts: total marked price = ₹1600; 25% of this is ₹400, matching the target rebate.

Why Other Options Are Wrong:
Any other count gives a total rebate not equal to ₹400 (e.g., 4 shirts → ₹320; 6 shirts → ₹480).

Common Pitfalls:
Confusing 25% of the total with 25% of the unit price (they are consistent, since total is linear in the count).

Final Answer:
5