perplexus.info :: Logic : Day-knights and night-knights 4

Day-knights and night-knights 4 (Posted on 2012-07-02)

There is a land where every inhabitant is either a day-knight or a night-knight. Day-knights tell the truth in the day and lie at night. Night-knights lie in the day and tell the truth at night. An inhabitant says, "Either I am a day-knight or it is day." Is the inhabitant a day-knight or a night-knight, and is it day or night?

Submitted by Math Man

Rating: 3.0000 (1 votes)

Solution: (Hide)

Suppose they are lying. Then, they are a night-knight and it is night, but night-knights tell the truth at night. Therefore, they are telling the truth, so either they are a day-knight or it is day. If they are a night-knight, then it is day, but night-knights lie in the day. Therefore, they are a day-knight and it is day.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Solution (including what "or" is meant)	Monika	2012-08-11 20:00:50
No twilight - Solution	Dej Mar	2012-07-02 12:33:18

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