Knights and Knaves: Judy, Heidi, Niaj, Bob, and Grace
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knights knaves
On an island, every inhabitant is either a knight, who always tells the truth, or a knave, who always lies. You meet Judy, Heidi, Niaj, Bob, and Grace.
Judy says: "Heidi is a knave."
Heidi says: "Grace is a knight."
Bob says: "Niaj is a knave and Grace is a knight."
Grace says: "If Niaj is a knight, then Judy is a knight."
The others say nothing.
Who is a knight and who is a knave?
Hints
Hint 1
Hint 2
Hint 3
Solution
Commit an attempt to unseal the proof. Write your answer — right or wrong, thinking it through is the point.
Once you've worked out who is who: how many of the 5 inhabitants are knaves? Answer with the number.
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