calculus
posted by lisa .
I have spilled 200cm^3 of vegetable oil on my kitchen floor. The resulting oil slick can be modeled as a cylinder with a very small height; the height is decreasing at a rate of 1/1000πcm/sec and the radius is currently 50cm.
How quickly is the radius of the oil slick increasing, in cm/sec?

V=PI*r^2 h
dv/dt=0=PIr^2 dh/dt + 2PI r h dr/dt
solve for dr/dt, you are given dh/dt.