+556 There are seven wombats in a council. Three of them are hairy-nosed wombats, while the rest are all different species. If the hairy-nosed wombats are indistinguishable but the other wombats are, how many ways can the wombats seat themselves in a row?
+355 You can position all of the wombats in 7! ways BUT you have over counted the 3 hairy wombats. So the answer is:
7!/3! = 840
35, or 7! / 3!*4!. This is equal to the number of ways that a group of 3 objects can fill seven cells,
with the remaining 4 objects mixed in.
+118613 There are seven wombats in a council. Three of them are hairy-nosed wombats, while the rest are all different species. If the hairy-nosed wombats are indistinguishable but the other wombats are, how many ways can the wombats seat themselves in a row?
The real meaning of this question is difficult to determine....
I think that both answers have merit.
there are 840 different ways that the wombats can sit, just like NinjaAnswer said,
but if you only care about the position of the 3 hairy nose wombats then I think out guest is correct. :)
+556 A fair coin is flipped 7 times. What is the probability that at least 5 consecutive flips come up heads?
