Coffee is draining form a conical filter into a coffee pot at the rate of 10 in^3/min. The diameter of the filter is 6 inches and the height is also 6 inches. How fast is the level of coffee in the cone filter falling when the coffee in the cone is 5 inches deep?
(Note: The volume of a cone is given by V = 1/3 pi r^2 h)

I'm extremely confused by this problem and am unsure if I'm suppose to solve for dr/dt or not and how to do so?