Columba has two dozen each of n different coloured beads. If she can select 20 beads (with repetition of colors allowed) in 230,230 ways, what is the value of n?
I'm trying to figure it out, but I'm having some trouble. I know that the question is asking how many colors are there, but I'm not sure how to go about getting there. Is there an applicable formula? And if so, what's it called?