Employees of a painting service paint the interior walls of homes and office buildings. the following table shows the number of cans of paint the employees use, and the number of square feet they cover.

cans of paint | 1 | 2 | 3 | 4
area painted (square feet) | 375 | 750 | 1125 | 1500

which equation describes the relationship between the number of cans of paint used, and the number of square feet that are covered?