a word problem

[drewski92]

I need help with three word problems and i don't know how to even start with these three.

This is problem number 1
A conical plastic bin (point down) is 5m in radius and 8m in height. Plastic pellets are being drawn out of the bottom at 50 cubic cm/sec. How fast is the depth of the plastic pellets decreasing when the height is 2m?

thanks i need the steps

 

[wjm11]

A conical plastic bin (point down) is 5m in radius and 8m in height. Plastic pellets are being drawn out of the bottom at 50 cubic cm/sec. How fast is the depth of the plastic pellets decreasing when the height is 2m?

http://tutorial.math.lamar.edu/Classes/CalcI/RelatedRates.aspx