Connected Rates of Change - Example (3)
Finally a Cone Problem - These can be tricky, learn the method.
Problems on cones can be quite tricky so I would encourage you to look at this example. It also demonstrates decreasing functions.
A cone of height 10 cm and base radius 3 cm is held vertex down and is filled with sand. A hole in the bottom of the cone allows the sand to escape at a steady rate of 0.5 cm3 s-1. Find the rate that the deptrh is decreasing when the depth is 2 cm.