1
$\begingroup$

Possible Duplicate:
What is the expression for putting $n$ indistinguishable balls into $k$ indistinguishable cells?

I think that this is quite basic, but I can't seem to get it:

Given $n>0$ identical oranges, and $k \leq n$ identical kids. In how many ways can I divide the oranges between the kids, when every kid gets at least one orange.

Notice that the kids are also identical! I.e it's not two different cases when we switch the amount of oranges between 2 kids.

Thanks!

  • 1
    are the oranges replaced after given to one kid or not?2011-12-21
  • 0
    @168335 I'm not sure I understand what you mean by replaced.. There are $n$ oranges. after you decide to give $m$ to one of the kids, there are $n-m$ left. I hope that's answers your question2011-12-21
  • 0
    This is an irrelevant comment, but you cannot distribute identical oranges, even less to identical kids. Say you want to give an orange to a kid, you grab for a first orange, but there isn't any first orange, they're all identical! Same problem with the kids. Anyway, for this kind of problem look at the [Twelvefold Way](http://en.wikipedia.org/wiki/Twelvefold_way#case_snx).2011-12-21

1 Answers 1