An island has only two types of people: Knights (who always speak the truth) and Knaves (who always lie).
I met two men who lived there and asked the taller man "Are both of you Knights?".
He replied with a "Yes" or "No", but from his answer, I could not figure out what type of person each man was.
I then asked the shorter man "Is the taller man a Knight?".
He replied with a "Yes" or "No", and after that I knew which type of person each man was.
Were the men Knights or Knaves?
by
Kai Hsien Boo
