related rates of a snowball

Question

A spherical snowball is melting in such a way that its radius is decreasing at rate of 0.4 cm/min. At what rate is the volume of the snowball decreasing when the radius is 16 cm.

(Note the answer is a positive number).

Please help!

Answer 1

V = (4/3)*pi*R^3

dV/dt = 4 * pi * R^2 * dR/dt

when r=16 ---> 4 * pi * 16^2 * 0.4

= 1,286.7963509103793104742987297913