Knights and Knaves: Peggy, Judy, Mallory, and Dave

Verified— unique solution

knights knaves

On an island, every inhabitant is either a knight, who always tells the truth, or a knave, who always lies. You meet Peggy, Judy, Mallory, and Dave. Peggy says: "Dave is a knave and Mallory is a knight." Judy says: "I am a knave or Dave is a knave." Mallory says: "I am a knight and Judy is a knave." 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 4 inhabitants are knaves? Answer with the number.

Hints

Solution

Comments