A very special island is inhabited only by knights and knaves. Knights always tell the truth, and knaves always lie. You meet 6 inhabitants: Penelope, David, James, Mia, Noah, and Scarlett. Penelope noted, "James is a knight or Scarlett is a knave". "If Noah is a knight then Penelope is a knight," David mentioned. "If Mia is a knight then Penelope is a knave" - James. Mia remarked, "Noah is not a knave". "Scarlett is a knave and Mia is a knave," Noah declared. In a statement by Scarlett: "Mia is not a knight". So who is a knight and who is a knave?
Penelope is a knight, David is a knight, James is a knight, Mia is a knave, Noah is a knave, and Scarlett is a knight.
(1) Penelope is a knight
(2) David is a knight
(3) James is a knight
(4) Mia is a knave
(5) Noah is a knave
(6) Scarlett is a knight
Assume Penelope is a knight. No contradiction is found in their claim that James is a knight or Scarlett is a knave. Assume James is a knight. No contradiction is found in their claim that If Mia is a knight then Penelope is a knave. Mia cannot be a knight, because this would contradict the claim of James that If Mia is a knight then Penelope is a knave. Assume Mia is a knave. No contradiction is found in their false claim that Noah is not a knave. Noah cannot be a knight, because this would contradict the false claim of Mia that Noah is not a knave. Assume Noah is a knave. No contradiction is found in their false claim that Scarlett is a knave and Mia is a knave. Assume Scarlett is a knight. No contradiction is found in their claim that Mia is not a knight. Assume David is a knight. No contradiction is found in their claim that If Noah is a knight then Penelope is a knight.