Concept:With at most one lie, you need enough questions to overcome the ambiguity caused by the lie.
Explanation:• There are only two possible results (Team A wins or Team B wins).
• Each question yields a “yes” or “no” answer, but at most one answer can be a lie.
• With two questions, the possible answer patterns for the true result “Yes” are: (Y,Y), (Y,N), (N,Y). For “No”: (N,N), (N,Y), (Y,N).
• The patterns (Y,N) and (N,Y) appear in both sets, so you cannot uniquely determine the true result.
• With three questions, you can ask the same question three times. If there is no lie, all three answers match. If there is one lie, two answers agree and one disagrees. The majority gives the correct result.
• Therefore, three questions are necessary and sufficient.
Answer:3