I have a rather simple math question:

If I have five (5) colors and use them four (4) times, how do I compute the UNIQUE number of combinations.

An example:

If I choose two (2) colors = Green and Black. I get duplicates like:

GGKK = GKGK = KGKG = GKKG = KGGK or

GKKK = KGKK = KKGK = KKKG

Can somebody help me in knowing how to mathematically calculate the UNIQUE count???

JTAshbywrote:Well duplicates like Green-Green-Black-Black is still identical to Black-Black-Green-Green.

In BOTH cases there are 2 Green and 2 Black.

JTAshbywrote:Well I have five (5) colors (n=5) and want to pick four (4) (r=4) of them.

BUT I don't know HOW to eliminate duplicates (as I mentioned above) :(

This is a *Tricky* problem...