Question

The table shows the cost to have various numbers of pizzas delivered from Papas Slice of Italy pizzeria. Is the relationship between the cost and the number of pizzas proportional? Explain.

Answer 1

12.5x-5(x-1)

Explanation:

you can find the pattern easily

it simplifies as

12.5x-5x+5=7.5x+5

Answer 2

Answer: No

Explanation:

We know that the equation for direct proportion between two quantities x ( independent variable) and y (dependent variable) is given by :-

`y=kx` , where k is the proportionality constant.

if the relationship between the cost (dependent variable ) and the number of pizzas (independent variable ) is proportional, then k in the above equation remains constant for each row.

Let
`k=\frac{\text{Cost }}{\text{Number of pizzas}}`

1)
`k=(12.50)/(1)=12.50`

2)
`k=(20)/(2)=10`

But 10≠12.50, thus the value for k is not fixed.

Hence, the relationship between the cost and the number of pizzas is not proportional.