An item is sold with a 25% discount on its marked price, and an additional promo code gives 4% cashback on the amount paid after discount. What is the effective overall discount received by the customer?

Introduction / Context:
This question combines the ideas of discount and cashback, both expressed as percentages. It tests whether the learner can correctly interpret how successive reductions and returns are computed relative to the marked price. Many shoppers meet similar offers in real life, so understanding the effective discount helps in practical decision making as well as examinations.

Given Data / Assumptions:
- An item has a marked price, say M rupees.
- A flat discount of 25 percent is first applied to the marked price.
- On the reduced price (the bill amount), a cashback of 4 percent is given to the customer.
- We are asked to find the effective discount as a single percentage on the original marked price M.

Concept / Approach:
The effective discount is calculated by comparing the net amount actually paid by the customer (after discount and cashback) with the original marked price. The 25 percent discount clearly reduces the bill, while the 4 percent cashback returns some money from the amount paid after discount. We treat the cashback as a further reduction to the net cost to the customer, but it is computed as a percentage of the already discounted price, not of the original marked price.

Step-by-Step Solution:
Let the marked price be M. First discount is 25 percent, so price after discount = M * (1 - 25 / 100) = M * 0.75. This discounted price is the basis for cashback. Cashback is 4 percent of 0.75M, so cashback amount = 0.04 * 0.75M = 0.03M. Net amount actually paid by the customer = discounted price - cashback. So net payment = 0.75M - 0.03M = 0.72M. This means the customer finally pays 72 percent of the marked price. Effective discount = (Marked price - Net payment) / Marked price * 100. Effective discount = (M - 0.72M) / M * 100 = 0.28 * 100 = 28 percent.

Verification / Alternative check:
Choose a simple value for M, for example M = 1000 rupees. After 25 percent discount, the price becomes 750 rupees. Cashback is 4 percent of 750 = 30 rupees. So the customer effectively pays 750 - 30 = 720 rupees. The effective discount is 1000 - 720 = 280 rupees. As a percentage, 280 / 1000 * 100 = 28 percent. This numerical check confirms our algebraic calculation.

Why Other Options Are Wrong:
29.12 percent and 29 percent: These values arise if one confuses successive percentage formulae or incorrectly treats cashback as an extra discount applied directly on the marked price.
5 percent: This ignores the first large discount and wrongly considers only the cashback effect.
25 percent: This takes into account only the first discount and ignores cashback, which provides additional savings.

Common Pitfalls:
Learners sometimes add 25 and 4 directly to get 29 percent, which is misleading because the 4 percent cashback is not on the original price but on the reduced amount. Another mistake is to think cashback does not change effective discount. In reality, any money returned to the customer reduces the net amount paid and therefore increases the effective discount. Always specify clearly what base each percentage is applied to and then compare the final net payment with the original marked price.

Final Answer:
The effective overall discount received by the customer is 28 percent of the marked price.