Dragon Eyes: #2
You come across a village and meet 5 dragons. You know that all dragons with blue eyes always tell the truth, while all red-eyed dragons always lie. You have also heard rumors of green-eyed dragons, who tell the truth, but their answers are inverted. Among green-eyed dragons, 'no' is 'yes' and 'yes' is 'no'. Each dragon is wearing goggles that obscure their eyes, so you can't tell how many have red eyes, and how many have blue eyes.
First, you ask "Do you have green eyes?"
Ainnanor: Yes.
Brathod: No.
Cheldrynth: No.
Dezzot: Yes.
Eithylot: No.
Having gained some information from that, you then ask "Do you have gold eyes?".
Ainnanor: Yes.
Brathod: Absolutely not. What kind of a question was that?
Cheldrynth: Yes.
Dezzot: unintelligible
Eithylot: I don't understand. None of us have gold eyes.
Is there a green-eyed dragon in the group? If so, which one is it? BONUS: What are the eye colors of all the dragons?
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1 solution
Cheldrynth is the only dragon with green eyes.
From your knowledge of the green-eyed dragons, you can eliminate Ainnanor and Dezzot after the first question, knowing that a green-eyed dragon would say "No."
The gold eyes question then reveals that Brathod and Eithylot cannot have green eyes, or they would have answered "Yes".
From an alternate point of view, Ainnanor cannot be telling the truth because then they would have both green and gold eyes, which is impossible. Brathod cannot be lying because then their eyes would be both green and gold. The same logic follows for Dezzot and Eithylot.