Question 22
A chess tournament uses a single round-robin format: each player is scheduled to play every other player once. After playing some games, Anh and Binh withdraw for health reasons. When the tournament finishes, 21 games have been played. How many players originally entered?
Clarification for this version: each withdrawing player has played at least one game, and their withdrawals leave at least one scheduled game unplayed. All games between the remaining players are completed.
Clarification for this version: each withdrawing player has played at least one game, and their withdrawals leave at least one scheduled game unplayed. All games between the remaining players are completed.