All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info
Home > Logic > Liars and Knights
These problems are from a very large set of questions about Liars who always lie about everything, and Knights who always tell the truth. Some questions also involve Knaves - people who strictly alternate between lying and telling the truth. (They are of course all indistinguishable from one another by outward appearance, and you must use logic to determine who's who.)
Difficulty: 4 of 5 Latest: John, Jack, A, and B Rating: 5.00
A logician named John went to the Land of Knights and Liars. He met two inhabitants, A and B. He asked A two questions.

John:Has B ever said that you are a liar?
A answered, either "Yes" or "No."
John:Is B a liar?
A answered, either "Yes" or "No."

The next day, another logician named Jack went to the Land of Knights and Liars. He met the same two inhabitants, A and B. He also asked A two questions.

Jack:Has B ever said that you are both liars?
A answered, either "Yes" or "No."
Jack:Is B a liar?
A answered, either "Yes" or "No."

One of the two logicians, John and Jack, could figure out what types A and B were, but the other logician could not figure out their types. What are A and B?

(No Solution Yet, 3 Comments) Submitted on 2024-07-09 by Math Man   
Page 2 of 13   << prev next >>    
Difficulty: 1 of 5Liar Logic 2 | Rating: 4.00
Posted on 2021-06-21 by Math Man (Solution Posted, 3 Comments)
Difficulty: 3 of 5Pages and Squires 2 |
Posted on 2020-10-08 by Math Man (No Solution Yet, 2 Comments)
Difficulty: 1 of 5Timothy and Elizabeth | Rating: 2.50
Posted on 2019-09-23 by Math Man (No Solution Yet, 4 Comments)
Difficulty: 5 of 5Knavish Arithmetic | Rating: 4.67
Posted on 2019-05-25 by FrankM (Solution Posted, 2 Comments)
Difficulty: 1 of 5Butcher, Baker, Doctor, and Lawyer | Rating: 5.00
Posted on 2019-04-02 by Charlie (Solution Posted, 1 Comments)
Difficulty: 2 of 5X and Y 2 |
Posted on 2019-01-28 by Math Man (Solution Posted, 4 Comments)
Difficulty: 3 of 5The trio |
Posted on 2017-08-21 by Math Man (Solution Posted, 1 Comments)
Difficulty: 2 of 5Candy lover |
Posted on 2017-06-12 by Ady TZIDON (No Solution Yet, 3 Comments)
Difficulty: 3 of 5Liars can figure | Rating: 2.00
Posted on 2017-04-24 by Ady TZIDON (Solution Posted, 4 Comments)
Difficulty: 3 of 5Lies, truth, and logic | Rating: 1.00
Posted on 2017-02-09 by Ady TZIDON (No Solution Yet, 2 Comments)
Difficulty: 1 of 5Legally Blonde | Rating: 3.00
Posted on 2016-12-19 by Math Man (No Solution Yet, 10 Comments)
Difficulty: 3 of 5Find the killer | Rating: 5.00
Posted on 2016-06-20 by Ady TZIDON (Solution Posted, 5 Comments)
Difficulty: 1 of 5Never on Sunday |
Posted on 2016-04-21 by Ady TZIDON (Solution Posted, 3 Comments)
Difficulty: 1 of 56 or less liars | Rating: 3.50
Posted on 2015-11-13 by Ady TZIDON (Solution Posted, 17 Comments)
Difficulty: 2 of 5Island Adventure 2 | Rating: 3.00
Posted on 2015-04-21 by Math Man (No Solution Yet, 4 Comments)
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (4)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (10)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information