Knights and Knaves: Dave, Heidi, Peggy, Rupert, and Sybil

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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 Dave, Heidi, Peggy, Rupert, and Sybil. Heidi says: "Peggy is a knave or Dave is a knave." Peggy says: "Rupert is a knave or Sybil is a knight." Rupert says: "Sybil is a knave and Heidi is a knave." Sybil says: "Rupert is a knight." The others say nothing. Who is a knight and who is a knave?

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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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