Answer:
See attachment for graph
Explanation:
Given

Required
Graph the relationship between both parameters
First, calculate the area;


This implies that: (2, 120) i.e. 2 cans for 120ft^2.
So we have:
(0,0) and (2,120)
(0,0) implies that: 0 cans for 0 square feet
Calculate the slope:




The equation is:

So, we have:



See attachment for graph