Possible Duplicate:
Number of different necklaces using $m$ red and $n$ white pebbles
I don't understand high level maths. Please try to do simple$\ldots$ I tried to hunt down the pattern but couldn't complete as I have my exam.
Possible Duplicate:
Number of different necklaces using $m$ red and $n$ white pebbles
I don't understand high level maths. Please try to do simple$\ldots$ I tried to hunt down the pattern but couldn't complete as I have my exam.
[Edit] Sorry, I was not aware that necklaces are considered equivalent up to rotation. Thanks to sdcvvc for correcting
This solution is only right for situations, where rotations are not equivalent:
(n+m)! / (n! * m!)
You have n+m
Beads and (n+m)!
ways to order them. But you have to ignore the order of black beads and the order of white beads. There are n!
permutations (possibilities to order) of black beads and m!
permutations of white beads. So you have (n+m)! / (n! * m!)
ways to order the beads.