If `n` biscuits are distributed among `N` beggars, find the chance that a particular beggar will get `r(ltn)` biscuits.

Explanation

There are total biscuits

N beggars

n biscuits can be distributed in `N^n` ways

to N beggars

P=(favourable outcomes)/(possible)`=(.^nC_r(N-1)^(n-r))/N^n`