What to do? At what rate is cone's vol. changing when r=10?

[think.ms.tink]

The radius of a right circular cone is increasing at a rate of 2 inches per second and its height is decreasing at a rate of 3 inches per second. At what rate is the volume of the cone changing when the radius is 10 inches and the height is 20 inches?

 

[BigGlenntheHeavy]

Re: What to do?

Volume of a right circular cone is {Pi/3)(r^2h), so dV/dt = (Pi/3)[2rh(dr/dt)+r^2(dh/dt)].

Can you take it from here?

 

[think.ms.tink]

Re: What to do?

i got 1100pi/3. it says im still wrong. thank you.

 

[stapel]

How did you get your answer? Why do you think your answer is incorrect?

Please reply showing your steps and reasoning. Thank you!