What radius would equal 24(pi) times this radius?

For my algebra class, this is the only question im stuck on this section:

Grain silos can be described as a hemisphere sitting atop a cylinder. The interior volume V of the silo can be modeled by V = 2/3(pi)r^{3} + (pi)r^{2}h Where h=height of a cylinder with radius r. For a cylinder 6m tall, what radius would give the silo a volume that is numerically equal to 24(pi) times this radius?

That's the problem, word-for-word verbatim. 2/3 is a fraction and pi is the symbol for (pi). I'm lost (Speechless) How do I use the Latex thing so I can type it out exactly as it appears?

Any help would be greatly appreciated.

Re: What radius would equal 24(pi) times this radius?