Ten Islanders and the Count of Knaves
On an island every inhabitant is either a knight (always tells the truth) or a knave (always lies). Ten islanders stand in a line, numbered 1 to 10. Islander number $k$ says: "At least $k$ of the ten of us are knaves." How many of the ten are knights? Give a single integer.
Related problems & prerequisites
Worth solving first
- Twice as Old as You Were 3.0/10
Source: Counting-statement puzzle in the knights-and-knaves tradition of Raymond Smullyan. Statement written for AxiomIQ.