1. **State the problem:** Calculate the total cost when buying a computer at its regular price and a printer with a 40% discount. 2. **Given data:** - Regular price of computer = 1200 - Regular price of printer = 300 - Discount on printer = 40% = 0.40 3. **Formula for discount price:** $$\text{Discounted Price} = \text{Original Price} \times (1 - \text{Discount Rate})$$ 4. **Calculate the discounted price of the printer:** $$300 \times (1 - 0.40) = 300 \times 0.60 = 180$$ 5. **Calculate total cost:** $$\text{Total Cost} = \text{Price of Computer} + \text{Discounted Price of Printer} = 1200 + 180 = 1380$$ 6. **Answer:** The total cost of the computer and the printer at the promotional price is **1380**.