2. Variant 1.

In the game "Mathematical Running," nine teams participated (not necessarily equal in the number of participants). On average, there were 7 people in each team. After one team was disqualified, the average number of participants in the remaining teams decreased to 6. How many participants were in the disqualified team?
Answer: 15.

Solution. The total number of participants before disqualification was $7 \cdot 9=63$. After the disqualification of participants, $6 \cdot 8=48$ remained. Therefore, the number of participants in the disqualified team was $63-48=15$.