All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Logic
Day-knights and night-knights 7 (Posted on 2013-11-25) Difficulty: 3 of 5
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.

Members of the Smith family are day-knights and members of the Jones family are night-knights.

Three inhabitants Al, Ben and Cal approach a visitor to the island. It is known that precisely two of them are members of the Jones family and the remaining one is a member of the Smith family.

They say:
Al: Ben belongs to the Jones family. 
Ben: Cal belongs to the Jones family. 
Cal: Alís surname is Smith.
What are the surnames of the three inhabitants? Is it day or night?

No Solution Yet Submitted by K Sengupta    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution solution Comment 1 of 1
which is Smith   D/N     stmt that can't exist
                         (not necessarily the only one)
    A             D       Ben's
    B             D
    C             D       Cal's
    A             N       Al's
    B             N       Al's
    C             N       Ben's


   
So it's Ben Smith telling the truth; the others are Joneses and it's daytime.
   


  Posted by Charlie on 2013-11-25 14:01:08
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (2)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information