Answer: 25 tickets
Explanation:
1. Gather the information: 125 tickets, gets 5 tickets per game, plays 20 games.
2. Find how many tickets he earned: since he played 20 games and gets 5 tickets per game, you multiple 20 by 5, and get 100 tickets. Therefore, he earned 100 tickets.
3. Find the original amount of tickets: we are asked to find how many tickets each student had at the start, so we subtract the amount Jackson earned (100) from his total (125). This leaves us with our final answer: 25.