A shop offers a promotion on dupattas: if a customer buys 6 dupattas priced at Rs. 1200 each, they receive 3 additional dupattas free.\nWhat is the effective discount percentage on each dupatta compared to its marked price?

Introduction / Context:
Promotional offers such as “buy some, get some free” are very common in real life and in aptitude exams. Although no explicit percentage is mentioned, such offers can be converted into an equivalent discount percentage to compare offers. This question asks you to find the effective discount on each dupatta when 3 pieces are given free on the purchase of 6, all with the same marked price.

Given Data / Assumptions:

• Marked price of one dupatta = Rs. 1200.
• Customer buys 6 dupattas and pays for all 6 at marked price.
• Customer receives 3 extra dupattas free.
• Total dupattas received = 6 paid + 3 free = 9 dupattas.
• We must find the effective discount percentage on each dupatta relative to its marked price of Rs. 1200.

Concept / Approach:
The key idea is that the customer pays a certain total amount but receives more items than they pay for. So the effective price per dupatta is the total amount paid divided by the total number of dupattas received. Once we know this effective price per piece, we compare it with the marked price to get the effective discount in rupees, and then convert that discount into a percentage of the marked price.

Step-by-Step Solution:
Step 1: Total amount paid = price of 6 dupattas = 6 * 1200 = Rs. 7200. Step 2: Total number of dupattas received = 9. Step 3: Effective price per dupatta = total paid / number of dupattas = 7200 / 9. Step 4: Compute 7200 / 9 = 800, so effective price per dupatta is Rs. 800. Step 5: Marked price per dupatta = Rs. 1200, so discount per dupatta = 1200 - 800 = Rs. 400. Step 6: Effective discount percentage = (400 / 1200) * 100 = (1 / 3) * 100 ≈ 33.33 percent.

Verification / Alternative check:
Think of it as paying for 6 pieces and getting 9, which is effectively paying for 2/3 of the total pieces (since 6 is two thirds of 9). Thus the customer pays 66.67 percent of the total marked value and gets 33.33 percent effectively free as discount. This gives the same discount rate: 100 percent - 66.67 percent ≈ 33.33 percent.

Why Other Options Are Wrong:
25 percent: This would mean effective price per piece is 75 percent of 1200, which is 900, not the 800 we computed.

30 percent: Would give an effective price of 70 percent of 1200, which is 840, also not supported by the total paid and received.

12.5 percent: Far too small; this corresponds to paying 87.5 percent of the price, much higher than the actual 66.67 percent.

50 percent: Would imply getting half the value free, which would require a different offer such as buy 1 get 1 free.

Common Pitfalls:
A common mistake is to treat the free dupattas as a flat percentage discount on the amount paid for the 6 pieces, rather than accounting for the fact that the free items are part of the total quantity received. Another error is to use 3/6 directly as 50 percent without considering the full 9 items. Always base the calculation on the total number of items received versus the total payment.

Final Answer:
The effective discount on each dupatta is approximately 33.33 percent of the marked price.