Question

7. For a party, Allison orders 15 pizzas. Some of the pizzas are pepperoni and cheese and cost $11.50 each. The rest of the pizzas are deluxe and cost $15.25 each. The total cost for the pizzas including a $5 delivery charge is $200. How many of the pizzas are deluxe?​

Answer 1

6 deluxe pizzas

Explanation:

200-5=195

195 is the total cost of pizzas

195=11.50x+15.25y

y=−0.75x+12.79

(the y intercept and slope are rounded)

x is reg. pizzas. y is deluxe

x+y=15

y=-x+15

if you plot both y=-x+15 and y=-0.75+12.79 you get coordinates that round to 9,6

9 pizzas

6 deluxe pizzas.