Answer:
B. 5 gallons per minute.
Explanation:
The tub is being filled when the volume is increasing. That is, at the point where the graph has a positive slope.
To find the rate at which the tub is being filled, pick two points from the part of the graph marked with red above.
They are: (4,20) and (0,0).
Next, find the rate of change.
[tex]\text{Rate of change=}\frac{20-0}{4-0}=\frac{20}{4}=5\text{ gallons per minute}[/tex]
The tub is being filled at a rate of 5 gallons per minute.
