A king invited the kings of neighboring countries to a peace meeting, but when they arrive at his castle he finds that he does not know where each king is from, all he knows is that the king of the north always lied, the one of the south he always told the truth, and the one from the east alternated between lying and telling the truth.
When you ask them, this is what one of them answers:
- I am not the king of the south, said A.
- B is not the king of the north.
- C is not the king of the east.
Can you determine which king is A, which is B and which is C?
A must be the king of the east because it would be false if it were the one from the south and true if it is not, that would also rule out the one from the north as it always lies.
From that, the second statement is false and the third one true; B is the king of the north and C is the south.