Calculus Related rates problem. Help!!!!!!?

Hi could someone please help solve and explain this calculus related rates math problem to me. I keep getting the wrong answer. Thanks!!! A closed cylindrical can of constant base radius 5 cm has its height increased at 0.1cm/sec from an initial 10cm. Hence, find the rate of change of a) the external surface... show more Hi could someone please help solve and explain this calculus related rates math problem to me. I keep getting the wrong answer. Thanks!!!

A closed cylindrical can of constant base radius 5 cm has its height increased at 0.1cm/sec from an initial 10cm.
Hence, find the rate of change of
a) the external surface area and
b) the capacity (volume) of the can,
20 seconds after the height increase commenced.

NOTE: the anser is a)π cm^2/sec and b) 2.5π cm^3/sec
5 answers 5