One Knight, One Knave, Two Normals
Four people, Ana, Ben, Cal and Dee, are exactly one knight (always truthful), one knave (always lying) and two normals (each statement may be true or false, at will). They say: - Ana: "Dee is not a knave." - Ben: "Dee is of the same type as Ana." - Cal: "Exactly one of Cal and Dee is normal." - Dee: "Cal is of the same type as Ben." Who is the knight? Answer with the name.
Related problems & prerequisites
Worth solving first
- Five Islanders and Their Conditionals 7.0/10
- Who Broke the Vase 7.0/10
- The Weekday Liar 7.0/10
Source: Original puzzle using Smullyan's 'normal' inhabitants from What Is the Name of This Book? (1978). Statement written for AxiomIQ.