The first person can be any one of 6. For each of those . . . The second person can be any one of the remaining 5. For each of those . . . The third person can be any one of the remaining 4.
Total number of ways to pick 3 people out of 6 = (6 x 5 x 4) = 120 ways.
BUT . . .
For each 3-person team, there are (3 x 2 x 1) = 6 ways to pick the same three people.
In the 120 ways to pick 3 people, you'll find each different group of 3 people picked 6 times, in a different order.
