Here's my problem

Sand falls out of the end of a slurry at the rate of 60 cc/sec. The pile forms a circular cone, the ratio of whose base diameter to height is 3. When the pile is of height 10 cm., at what rate is the height of the pile increasing?

So far I have $\displaystyle V=\frac{1}{3}(\pi)r^2h$ where $\displaystyle r=\frac{2h}{3}$ but then I can't seem to figure out the rest of the problem. Any help is greatly appreciated.