1. The problem statement, all variables and given/known data Gravel is being dumped from a conveyor belt at a rate of 30 cubic feet per minute. It forms a pile in the shape of a right circular cone whose base diameter and height are always the same. The height of the pile is increasing at a rate of ____ feet per minute when the pile is 11 feet high. Recall that the volume of a right circular cone with height h and radius of the base r is given by (1/3)*pi*(r^2)*h. 2. Relevant equations Noted above. 3. The attempt at a solution I don't understand the problem. If the radius and the height are always the same how can they change? EDIT: if I am thinking of this correctly then the answer would be 0 (which is incorrect).