# Math Help - differential equation from related rate of change.

1. ## differential equation from related rate of change.

A cylinderical hole is of height H and radius R .. it has a conical portion of same height and radius equal to 1/3rd the height which was removed.. rain is falling at a rate of pi per second... how much time will it take for the hole to be full ?

2. How do you "remove" a conical portion from a cylindrical hole? Can you draw a picture?