Answer:
1/2!(12, 2)(10, 5)
Explanation:
Let's pick 2 persons for team one. We can do that in (12, 2) ways. Then, let's pick five of the remaining people for team two. We can do that im (10, 5) ways. Five remaining people form team three., because the order of teams foes not matter divide the team by 2! (we have 2 teams with five people). Thus the final answer is 1/2!(12, 2)(10, 5)