Question 3
Five teams A, B, C, D and E play a single round-robin football tournament: every pair plays exactly once. A win earns 3 points, a draw 1 point for each team, and a loss 0 points. Their final totals are A: 10, B: 7, C: 6, D: 6, E: 0. Prove that exactly one match is drawn and identify the two teams in that match.
