A person says: 'I am a knave.' Is this person a knight or knave?
You stand before two doors. One leads to freedom, one to doom. Two guards stand watch — one always tells the truth (knight), one always lies (knave). You don't know which is which. You can ask ONE guard ONE question. What do you ask?
Three people A, B, C are either knights (always true) or knaves (always lie). A says: 'We are all knaves.' B says: 'Exactly one of us is a knight.' What are A, B, and C?
Three guards stand at a gate. Guard 1: 'Guard 2 is a knight.' Guard 2: 'Guard 1 is a knave.' Guard 3: 'Guard 2 is a knave.' How many guards are knights?