Answer:
Step-by-step explanation:
With an eight team round robin, 28 games will be played in total (The total edges in K8). Since each game will produce two points regardless of outcome, 56 total points will be shared among the eight teams. In the absence of a well-defined tie breaking system, we assume that ties do not qualify as a guarantee. We define a team's point total as "ensuring" fourth place when the fifth place team could not possibly have that many points.
Ten points are not enough and eleven points must be enough. In one extreme case, teams A,B,C,D and E all draw each other and win against F,G, and H (who also draw each other), giving a fifth place team with ten points. If we have a fifth place team with eleven points then teams A,B,C,D, and E share at least 55 points, meaning teams F,G, and H share at most one point. However, F,G, and H play each other and must share at least six points, a contradiction. Therefore, 11 points guarantees fourth place at a minimum.
