Question 1109283: A baseball manager has 11 players of the same ability. How many 9 players starting lineups can he create Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! That is 11C9 or 11!/9!2!
That is 11*10/2=55
11!=11*10*9!
11!/9! is therefore 11*10
That is divided by 2