  The following class of problems arose out of vain attempts to show that the
Pascal's triangle adic transformation has trivial spectrum. Partition a set of
size $N$ into sets of size $S \equiv S(N)$ (ignoring leftovers). What is the
likelihood that a set of size $K \equiv K(N)$ will intersect each set in the
partition in at least $R \equiv R(N)$ members (as $N$ increases)? Via
elementary techniques and under reasonable hypotheses, we obtain an easy-to-use
formula. Although different from the corresponding minimum problem for balls
and bins (with $m = K$ balls and $n = N/S$ bins), under modest constraints, the
asymptotic probabilities are the same.
