Answer :
Answer:
There's a proportion relationship between number of shell and their cost
Step-by-step explanation:
The graph is not given.
However, I've added the appropriate graph as an attachment.
From this, point....
I'll show that the cost and number of shells as given in the question are proportional.
Represent cost with y and number of shells with x
x = 2 when y = 0.8
x = 3 when y = 1.2
x = 4 when y = 1.6
Divide each value of y by x to get the constant of proportion (r).
r = y/x
r = 0.8/2 = 0.4
r = 1.2/3 = 0.4
r = 1.6/4 = 0.4
Notice that the values of r remain constant.
Hence, there's a proportion relationship between both
And what this rate represent is that:.the cost of shell changes at a constant rate when the number of shell is changes.

The proportionality constant is same means that the cost of shell changes at a constant rate when the number of shells changes.
Given :
- Melanie buys 2 shells for $0.80.
- Rosi buys 3 shells for $1.20.
- Carlos buys 4 shells for $1.60.
The following steps can be used to determine there is a proportional relationship or not between the number of shells and their cost:
Step 1 - First determine the value of x and y from the given data.
Points - (2,0.8), (3,1.2), and (4,1.6)
Step 2 - Now, divide y by x in order to determine the proportionality constant.
[tex]r = \dfrac{0.8}{2} = 0.4[/tex]
[tex]r'=\dfrac{1.2}{3}=0.4[/tex]
[tex]r" =\dfrac{1.6}{4}=0.4[/tex]
Step 3 - Observe that the values of r, r', and r" are the same. Therefore, there is a proportional relation between them.
The proportionality constant is same means that the cost of shell changes at a constant rate when the number of shells changes.
For more information, refer to the link given below:
https://brainly.com/question/21328304