How many different signals can be sent up on a flag pole if each signal requires three yellow and three blue flags and the flags are identical except for color?
would this just be 6C3 times 6C3???
Since the total possible choices (6!) contains repeated arrangements,
Take the number of different arrangements as N.
Therefore, since there are three yellow flags and three blue flags interchanging them will will give you the total possible choices.
Hope this will clarify.