Explanation:

To find the single discount equivalent to two successive discounts of 10% and 15%:

- Start with an initial price of 100 units for simplicity.

- Apply the first discount of 10%: reducing the price to 100 - 10 = 90 units.

- Apply the second discount of 15% on the new price: reducing it further to \(90 \times 0.85 = 76.5\) units.

- The final price is 76.5 units, which is a total reduction of \(100 - 76.5 = 23.5\) units.

- Therefore, the equivalent single discount is \(\frac{23.5}{100} \times 100 \% = 23.5\%\).

- Option 1: 21.5% - incorrect.

- Option 2: 23.5% - Correct Answer

- Option 3: 25% - incorrect.

- Option 4: 26.5% - incorrect.