Each team needs to play against all teams except itself. Each team needs 5 games and 6 teams need 30 games. However, in the same game, both teams are counted and there is duplication. Divide by 2.
8 groups *** 15×8= 120 games.
There are 8×2= 16 teams in the second round.
Need 16- 1= 15 games.
1 person will be eliminated in each competition. The champion is only 1, which means that 15 people will be eliminated, and 15 people will be eliminated, so 15 games will be needed.