How to use the given hint to answer this question?
More Context for this question:
This problem refers to the classical occupancy problem (Boltzmann-Maxwell statistics): that is, r balls are distributed among n cells and each of the $n^r$ possible distributions has probability $n^{-r}$
When I insert r=3,n=2 as per Henry"s comment,I got '?' as an answer. How is that?
More information:
