There are 4 teams in total and each team has 7 members. One of the team will be the host team.
Tournament committee will be made from 3 members from the host team and 2 members from each of the three remaining teams. Selecting the members for tournament committee is a combinations problem. We have to select 3 members out 7 for host team and 2 members out of 7 from each of the remaining 3 teams.
So total number of possible 9 member tournament committees will be equal to:
This is the case when a host team is fixed. Since any team can be the host team, there are 4 possible ways to select a host team. So the total number of possible 9 member tournament committee will be:
Therefore, there are 2917215 possible 9 member tournament committees