Final answer:
To find the total added cost for Brian's pizza delivery, calculate the sales tax and tip based on the pizza cost and then add the delivery fee. The total additional cost to the pizza order will be $8.28.
Step-by-step explanation:
Calculating the Total with Delivery Fee, Sales Tax, and Tip
To calculate the total amount that will be added to Brian's pizza order, we need to first determine the subtotal before the delivery fee. The subtotal is the cost of the pizzas, which is $24. Next, we calculate the sales tax by converting the percentage to a decimal and multiplying it by the subtotal. The sales tax is therefore 0.07 × $24 = $1.68. Similarly, to calculate the tip, we convert the percentage to a decimal and multiply it by the subtotal, which gives us 0.15 × $24 = $3.60. Adding these to the delivery fee, the total extra cost would be $1.68 (sales tax) + $3.60 (tip) + $3.00 (delivery fee) = $8.28.