Explanation:

- The difference in selling price at 18% and 10.5% discounts is Rs 192.

- Let the marked price be Rs X.

- So, the selling price at 18% discount = X - 0.18X = 0.82X.

- The selling price at 10.5% discount = X - 0.105X = 0.895X.

- According to the question: 0.895X - 0.82X = Rs 192.

- This simplifies to: 0.075X = Rs 192.

- Solving for X gives: X = Rs 192 / 0.075 = Rs 2,560.

- Options:

1. Rs 2,580 – Incorrect

2. Rs 2,480 – Incorrect

3. Rs 2,560 – Correct

4. Rs 2,500 – Incorrect