Question

There are 25 players in a ping-pong tournament. Each player plays every other player exactly once. How many games will be played? I think have it then keep getting it wrong :(

Answer 1

This is a round robin style tournament. Given that there are 25 people, and order doesn't matter meaning that the combination AB is equivalent to BA you must use the choose formula. 

Thus the answer should be 25C2 or
25! / [(25-2)! * 2!] = 300