Question

A restaurant offers delivery for their pizzas. The total cost is a delivery fee added to the price of the pizzas. One customer pay $25 to have 2 pizzas delivered. Another customer pays $58 for 5 pizzas. How many pizzas are delivered to a customer who pays $80?

Answer 1

Answer

Find out the how many pizzas are delivered to a customer who pays $80 .

To prove

As given

A restaurant offers delivery for their pizzas.

The total cost is a delivery fee added to the price of the pizzas.

One customer pay $25 to have 2 pizzas delivered.

$Let\ us\assume\ cost\ of\ the\ one\ customer\ pay = x_{1} = 25$

$Let\ us\assume\ number\ of\ pizza = y_{1} = 2$

Another customer pays $58 for 5 pizzas.

$Let\ us\assume\ cost\ of\ the\ second\ customer\ pay = x_{2} = 58$

$Let\ us\assume\ number\ of\ pizza = y_{2} = 5$

Thus by using the slope formula

$m =\frac{y_{2} - y_{1}}{x_{2} - x_{1}}$

Putting the value in the formula

$m = \frac{5 - 2}{58 - 25}$

$m = \frac{3}{33}$

Simplify the above

$m = \frac{1}{11}$

This represented one pizza cost is $11.

Thus 2 pizza cost = $11 × 2

                              = $22

Thus

Delivery price = Total cost of 2 pizza including delivery fee - Cost of 2 pizza

                       = $25 - $22

                      = $3

Thus 5 pizza cost = $11 × 5

                              = $55

Thus

Delivery price = Total cost of 5 pizza including delivery fee - Cost of 5 pizza

                       = $58 - $55

                      = $3

Therefore the delivery charge is $3.

Now calculate the number of pizza for the customer who pays $80.

Cost of the pizza = Total cost of the pizza including delivery charges - Delivery charges

                            = $80 - $3

                           = $ 77

Let us assume that the number of pizza for the customer who pays $80 = x

Cost of one pizza = $11

Than the equation becomes

11 × x = 77

$x = \frac{77}{11}$

x = 7

Therefore the number of pizza are 7 delivered to a customer who pays $80 .