A conical reservoir has a depth of 24 feet and a circular top of radius 12 feet. It is being filled so that the depth of water is increasing at a constant rate of 4 feet per hour. Determine the rate in cubic feet per hour at which water is entering the reservoir when the depth is 5 feet.
I'm still knew to the whole finding rates of change thing but I know I'm suppose to find the derivative of the Volume, but I don't know how to deal with the equation afterward. Help?