I have 6 identical balls and 4 identical boxes to put them in. If each box contains at least 1 ball, how many possible distributions are there?
+310 We first put one ball in each box. Now we have 2 balls to distribute in 4 boxes. Since they are both identical, the cases are
3 1 1 1
2 2 1 1
So there are 2 possible distributions.
