Knights and Knaves: Carol, Ivan, Judy, Sybil, and Dave

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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 Carol, Ivan, Judy, Sybil, and Dave. Carol says: "Dave and Sybil are of the same type." Ivan says: "Sybil is a knight and Dave is a knight." Judy says: "Ivan is a knave and Dave is a knight." Sybil says: "Carol and I are of different types." Dave says: "Sybil is a knight or Carol is a knave." 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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