- There are 4  different possible arrangements of teams are there.
 
Explanation:
Lets understand the situation,
This means Each team can have 3, 4 or 5 people.And 21 people take part.
we have to find  How many different possible arrangements of teams are there.
Solution:-
Situation 1.
- if 7 groups of people 3 Team
 - 7×3=21.
 
situation 2.
- if 4 groups of people 4 teams and 1 group of people 5 Team.
 - (4×4)+(1×5)=21.
 
Situation 3.
- if 2 groups of people 3 Team and 3 group of people 5 Team.
 - (2×3)+(3×5)=21.
 
situation 4.
- if 4 groups of people 3 Team and 1 group of people 4 Team And 1 group of people 5 team.
 - (4×3)+(1×4)+(1×5)=21.