SOLUTION: How many different 10-letter words (real or imaginary) can be formed from the following letters? O Q P E K G Q W F Q

 O Q P E K G Q W F Q

If the Q's were of different colors like this:

 O Q P E K G Q W F Q

then the answer would be 10!.  However the Q's are
not different colors and we cannot tell them apart.
So we need to figure out how many times too many 10!
counts the 10-letter words.  In each arrangement of 
letters there are 3! ways to rearrange the 3 Q's. So
10! counts the arrangements 3! times too many, so 
the answer is .

Edwin