Question

You and a group of 7 friends go out for pizza. One large pizza and 3 medium drinks cost $21.96. One large pizza and 6 medium drinks cost $30.93. Write a linear function rule that models the cost of y (in dollars) for one large pizza and any number of drinks x. Use the linear function rule to estimate the cost of one large pizza and 8 medium drinks for you and your friends

Answer 1

Explanation:

x = cost of drink

y = total cost

First information: "one large pizza and 3 medium drinks cost $21.96":

3a + b = 21.96

Second information: "one large pizza and 6 medium drinks cost $30.93":

6a + b = 30.93

{3a + b = 21.96

{6a + b = 30.93

{- 3a - b = - 21.96

{6a + b = 30.93

3a = 8.97

a = 2.99

3a + b = 21.96

3•2.99 + b = 21.96

8.97 + b = 21.96

b = 21.96 - 8.97

b = 12.99

Each drink costs $2.99 and each pizza costs $12.99. The linear function rule is:

y = 2.99x + 12.99

I hope I've helped you.