SOLUTION: Five students hold a checkers tournament. In the first round, each of the students plays each of the other students just once. How many different games are played?

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Question 626467: Five students hold a checkers tournament. In the first round, each of the students plays each of the other students just once. How many different games are played?
Answer by Edwin McCravy(20067) About Me  (Show Source):
You can put this solution on YOUR website!
"5 choose 2", or "the combinations of 5 things taken 2 at a time".  It's
combinations, not permutations because order is not considered since 
A playing B is the same thing as B playing A.

C(5,2) = 5%21%2F%282%21%2A%285-2%29%21%29 = 5%2A4%2A3%2A2%2A1%2F%28%282%2A1%29%283%21%29%29 = 5%2A4%2A3%2A2%2A1%2F%28%282%2A1%29%283%2A2%2A1%29%29 = 10 

The 10 games are:

1. A and B play.
2. A and C play.
3. A and D play.
4. A and E play.
5. B and C play.
6. B and D play.
7. B and E play.
8. C and D play.
9. C and E play.
10. D and E play.

 Edwin