1. **Problem (a):** Find the original price of an oven sold at 25% off with a sale price of 251.85. 2. The formula for discount price is: $$\text{Sale Price} = \text{Original Price} \times (1 - \text{Discount Rate})$$ 3. Substitute the known values: $$251.85 = \text{Original Price} \times (1 - 0.25) = \text{Original Price} \times 0.75$$ 4. Solve for Original Price: $$\text{Original Price} = \frac{251.85}{0.75}$$ 5. Show cancellation step: $$\text{Original Price} = \frac{251.85}{\cancel{0.75}} \times \frac{\cancel{1}}{1}$$ 6. Calculate: $$\text{Original Price} = 335.8$$ 7. **Answer (a):** 335.80 8. **Problem (b):** Calculate the price of a 435 refrigerator after a $50 discount and then 15% off. 9. First apply the $50 discount: $$435 - 50 = 385$$ 10. Then apply 15% discount: $$\text{Final Price} = 385 \times (1 - 0.15) = 385 \times 0.85$$ 11. Calculate: $$\text{Final Price} = 327.25$$ 12. **Answer (b):** 327.25 13. **Problem (c):** Find the percent increase in sales from 52,900 to 78,300. 14. Percent increase formula: $$\text{Percent Increase} = \frac{\text{New} - \text{Old}}{\text{Old}} \times 100$$ 15. Substitute values: $$\frac{78,300 - 52,900}{52,900} \times 100 = \frac{25,400}{52,900} \times 100$$ 16. Calculate: $$0.48 \times 100 = 48\%$$ 17. **Answer (c):** 48%