The height of a grain of a cylindrical silo is is increasing at a constant rate of 4 feet per minute At what rate is the volume of grain in the cylinder if the radius of the silo is 10 feet?

Volume of cylinder
[tex]V = \pi h r^2 [/tex]

radius is given as 10
[tex]V = \pi h (10)^2 = 100\pi h[/tex]

Differentiate with respect to 't'
[tex]\frac{dV}{dt} = 100 \pi \frac{dh}{dt} [/tex]

dh/dt = 4

[tex]\frac{dV}{dt} = 100 \pi (4) = 400 \pi[/tex]