Question

Eight members of a chess club are having a tournament. In the first round every player will play a chess game against every other player. How many games will be in the first tournament

Answer 1

now, if every member is playing the other 7, that means each game will have two players, so, seems to me is, how many Permutations of 2 from a group of 8?


`\bf _nP_r=\cfrac{n!}{(n-r)!}\quad \begin{cases} n=8\\ r=2 \end{cases}\implies _8P_2=\cfrac{8!}{(8-2)!}`