Two islanders are each either a knight (always truthful) or a knave (always lying). A says: 'At least one of us is a knave.' What are A and B?
Answer and explanation
Correct answer: C. A is a knight and B is a knave
- Step 1: If A were a knave, the statement would be false, so neither would be a knave, which contradicts A being a knave.
- Step 2: So A is a knight and the statement is true, which needs at least one knave: B is a knave.
Answer
A is a knight and B is a knave.
Why not the others: A knave cannot tell the truth; two knights would make the statement false; two knaves would make it true, which a knave cannot say.
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