A sphere is losing volume at 6cm^3/minute

How fast is the radius of the sphere decreasing when the surface are of the sphere is 24cm^2?

"The volume of a sphere as a function of its radius is V=4pi/3*r^3. The surface area of a sphere as a function of its radius is SA=4pi*r^2."

This is given as a problem in a calculus chapter containing derivatives. I can't get my initial equation started at all.

The more I try to even think of it, I just complicate it more and more.

We are talking radius decreasing so its not the total volume. Otherwise I'd just write 6cm^3/minute.

Please help.