1. **Stating the problem:** A school bag is on sale at 15% off, and the sale price is 841.50. We need to find the original price before the discount. 2. **Understanding the discount:** A 15% discount means the sale price is 85% of the original price because $100\% - 15\% = 85\%$. 3. **Setting up the equation:** Let the original price be $OP$. The sale price is 85% of $OP$: $$841.50 = 0.85 \times OP$$ 4. **Solving for the original price:** Divide both sides by 0.85: $$OP = \frac{841.50}{0.85}$$ Calculate: $$OP = 990$$ 5. **Conclusion:** The original price of the bag is 990.