48 gallons... since the first shower head gives 9 gallons per minute you multiply 9 by 8 then you use the equation and multiply 3 by 8 then you subtract the two shower heads
Formula for finding the area of a rectangle: length x width
Formula for finding the volume of a rectangular prism: V = lwh
Since the graph is a linear function, we're going to use the slope formula solve this:
Note I am replacing m with k

Inserting 2 points from the graph, let's use (1,8) and (2,16).

k=8
What are the ^ supposed to mean multiplecation?
I think the best option is 24.