pacman23
pacman23 pacman23
  • 07-07-2018
  • Mathematics
contestada

In one round robin chess tournament, 36 games were played. How many players entered in the tournament?

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konrad509
konrad509 konrad509
  • 07-07-2018
[tex]\displaystyle \binom{n}{2}=36\\\\ \dfrac{n!}{2!(n-2)!}=36\\ \dfrac{n(n-1)}{2}=36\\ n(n-1)=72\\ n^2-n-72=0\\ n^2-9n+8n-72=0\\ n(n-9)+8(n-9)=0\\ (n+8)(n-9)=0\\ n=-8 \vee n=9[/tex]

The number of players can't be negative, so there was 9 players.


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