1. **Problem statement:** A computer has a regular price of 910 and is on sale for 20% off. We need to find: a) The price after the discount (excluding tax). b) The cost after adding 13% HST tax on the discounted price. c) Whether it makes a difference if tax is applied before or after the discount. 2. **Formula and rules:** - Discounted price = Original price - (Discount rate × Original price) = Original price × (1 - Discount rate) - Price after tax = Price before tax × (1 + Tax rate) - Important: Percentages must be converted to decimals for calculations (e.g., 20% = 0.20). 3. **Step a) Calculate discounted price:** Discount rate = 20% = 0.20 Discounted price = $910 \times (1 - 0.20) = 910 \times 0.80$ $$910 \times 0.80 = 728$$ So, the price after discount is 728. 4. **Step b) Calculate price after tax:** Tax rate = 13% = 0.13 Price after tax = Discounted price \times (1 + Tax rate) = 728 \times 1.13$ $$728 \times 1.13 = 822.64$$ So, the cost after tax is 822.64. 5. **Step c) Does order of applying tax and discount matter?** - Calculate tax first, then discount: Tax on original price = $910 \times 1.13 = 1028.30$ Discount on taxed price = $1028.30 \times (1 - 0.20) = 1028.30 \times 0.80$ $$1028.30 \times 0.80 = 822.64$$ - Calculate discount first, then tax (already done): 822.64 Both methods give the same final price 822.64. **Explanation:** Because multiplication is commutative, applying a percentage discount and then a percentage tax or vice versa results in the same final amount. **Final answers:** - a) 728 - b) 822.64 - c) No difference in final price whether tax is applied before or after discount.