Asandwich store charges $20 to have 3 turkey subs delivered and $26 to have 4 delivered.

is the relationship between number of turkey subs delivered and amount charged proportional? explain how you know.
how much does the store charge for 1 additional turkey sub?
describe a rule for determining how much the store charges based on the number of turkey subs delivered.

The store charges

If we order 3 turkey subs

$20/3 =  $6.66 per turkey sub

If we order 4 turkey subs, the order would be

$26/4 =  $6.5 per turkey sub

If we order 4 turkey subs, we get a price reduction per turkey sub.

So the relationship between the number of turkey subs ordered and the price is not proportional (linear)

We know this because as the order increases, we do not have the same cost per turkey sub.

$6.66 ≠ $6.5

If you order 3 turkey subs, you will pay $20 dollars or $6.66 per turkey sub

If you order 4 turkey subs, you will pay $26 dollars or $6.5 per turkey sub