Blue-eyed islanders
On an island, 100 of the inhabitants have blue eyes. All are perfect logicians who can never discuss eye color, but anyone who deduces their own eye color must leave at the following midnight. One day a trusted visitor announces, "At least one of you has blue eyes." On which midnight do the blue-eyed people leave?
Show hints (2)+
- Solve the n = 1 and n = 2 cases first.
- Induct: the absence of a departure on night n−1 is itself information.
Answer
Reveal answer →Final answer
100
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