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Logical Labyrinth: Problem 1.2
Problem 1.2 (A varian of 1.1:
According to another version of the story, Abercrombie didn't ask A whether he was a knight or a knave (because he would have known in advance what answer he would get), but instead he would ask A how many of the three were knaves. Again A would answer indistinctly, so Abercrombie asked B what A had said. B then said that A had said that exactly two of them were knaves. Then, as before, C claimed that B was lying.
Is it now possible to determine whether C is a knight or a knave?
(copied from Logical Labyrinth, by Raymond M. Smullyan)
_________________________
DON'T FORGET:
Edgar Abercrombie was an anthropologist who was particularly interested in the logic and sociology of "lying" and "truth telling". One day he decided to visit a cluster of islands where a lot of lying and truth-telling activity was going on! The first island of his visit was the Island of Knights and Knaves. (Knights always tell the truth; Knaves always lie)
According to another version of the story, Abercrombie didn't ask A whether he was a knight or a knave (because he would have known in advance what answer he would get), but instead he would ask A how many of the three were knaves. Again A would answer indistinctly, so Abercrombie asked B what A had said. B then said that A had said that exactly two of them were knaves. Then, as before, C claimed that B was lying.
Is it now possible to determine whether C is a knight or a knave?
(copied from Logical Labyrinth, by Raymond M. Smullyan)
_________________________
DON'T FORGET:
Edgar Abercrombie was an anthropologist who was particularly interested in the logic and sociology of "lying" and "truth telling". One day he decided to visit a cluster of islands where a lot of lying and truth-telling activity was going on! The first island of his visit was the Island of Knights and Knaves. (Knights always tell the truth; Knaves always lie)