Answer:
DIY water filtering costs
$33 = 3300 cents for 30 gallons =
11 cents per gallon
So the linear function is 38 + 0.33 G where G is the gallons of water
The $38 flat fee is for the water filter and the reusable water.
1 pack of bottled water is 3.16875 gallons ( 24 x 16.9 ounces with 128 ounces per gallon)
Using the filtering system, 3.16875 gallons will cost 0.33 x 3.16875 = $1.0456875
This is 3.99-1.0456875 = 2.94 cheaper per pack of water
38 / 2.94 = 13
So the filtering system will pay for itself after 13 cases of water
Explanation:
i explain it all up.