Questions tagged [liars]

Puzzles that focus on getting information from truth-tellers (who never lie), liars (who always lie), and/or Jokers (who answer at random), or which use such characters as an integral part of the puzzle.

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23
votes
5answers
4k views

Knights and Knaves : Liar , Liar - How many are you?

There are 2014 persons in a row Each of them is either a Knave (who always lies) or a Knight (who always tells the truth). Each person says 'There are more knaves to my left than knights to my ...
7
votes
4answers
3k views

Lying, truthful and merciless guards (variation)

This is a variation of the riddle of 2 guards and 2 doors: You are stuck in a room with 3 doors. Each of the doors have a guard posted. One guard always tells the truth, one always lies, and the ...
1
vote
3answers
3k views

Puzzle : Who is Corrupt in the Senate?

I was working my way through some puzzles in Discrete Maths by Rosen, when I came across the following question: Freedonia has fifty senators. Each senator is either honest or corrupt. Suppose you ...
45
votes
10answers
18k views

Puzzle: Who hacked the computer?

I was working my way through some Knight and Knave Puzzles in Discrete Maths by Rosen, when I came across the following question: Four friends have been identified as suspects for an unauthorized ...
2
votes
2answers
2k views

Knights , Knaves and Spies - Part 2

I was working my way through some Knight and Knave Puzzles in Discrete Maths by Rosen, when I came across the following question: There are inhabitants of an island on which there are three kinds of ...
10
votes
3answers
21k views

Knights , Knaves and Spies - Part 1

I was working my way through some Knight and Knave Puzzles in Discrete Maths by Rosen, when I came across the following question: There are inhabitants of an island on which there are three kinds of ...
3
votes
1answer
4k views

Is this a correct solution to determining which of two people is the liar using one question?

I was working my way through some Propositional Logic Questions in Discrete Maths by Rosen, when I came across the following question: An explorer is captured by a group of cannibals. There are two ...
13
votes
4answers
7k views

Who is the thief? An elementary school teacher had her purse stolen

This puzzle is not mine, but I couldn't find an original source. I edited it somewhat. An elementary school teacher had her purse stolen. The thief had to be Sammy, Karin, Arnold, Harry, or Liza. ...
1
vote
2answers
537 views

If The Knights and Knaves got together [closed]

If the island of knights and knaves got together and there were n people, including a joker, how many questions would it take for all of the knights and knaves found the joker? Nobody knows who each ...
17
votes
2answers
1k views

Automatically a Knight, Knave, and Joker

Let M be a finite positive integer. It's exact value is not known. Suppose we have three classes of automaton, all of which accept a bit stream as input, produce a bit stream as output (one bit per ...
2
votes
4answers
1k views

The way to Acarien, with Knights and Knaves

Once again, you're on your way to Acarien. You find yourself in a land of Knights and Knaves, who understand your language but don't speak it. You understand nor speak their language, but you do know ...
1
vote
1answer
293 views

T Knights, L Knaves and R Jokers with one question type only

I would like to try more strict conditions for puzzle, which frodoskywalker solved so simply. Basically all the same, but only one type of questions is allowed. We have T Knights (truth-tellers),...
9
votes
1answer
1k views

The Old Millionaire

A very old man has a million dollars, which he's going to pass down to you! He has 3 associates who have been ordered to help you. The 3 associates know the location where it is, and they tell you it ...
8
votes
3answers
1k views

Teenage Knight/Knave/Joker

You find yourself in the usual situation with three locals whose answering is highly restricted. First, they can only answer yes or no questions. Second, one will always answer truthfully, one will ...
2
votes
2answers
483 views

T Knights, L Knaves and R Jokers

Following these questions: Faulty computers, Knights and jokers I wonder, what if the conditions are the following: We have T Knights (truth-tellers), L Knaves (liars) and R Jokers (random-...
4
votes
2answers
1k views

Knight/Knave/Joker - impasse challenge

You are at an impasse with 30 doors - 29 of them lead to endless wandering the depths of hell - and one of them leads to paradise. In front of them stand the typical trio of good friends, a Knight, a ...
0
votes
2answers
513 views

Is there probability based Knight-Knave puzzles?

Have you seen Knight-Knave puzzles based on probability rather then facts? For example a puzzle with condition like this: Knight tells the answer, probability to which according to his knowledge is ...
4
votes
1answer
821 views

The knaves come out at night

Standard knights and knaves problem. There are 10 people in a room, you know that each person will either always tell the truth or always lie, but you don't know who is a truth teller or liar. You ...
-4
votes
3answers
16k views

Crossroad with an Indian from one of two tribes [duplicate]

You are on a trail in a desert. You already drank all your water, and are 2 miles from the next well. There is a crossroads in the trail. One path leads directly to the fountain, and one leads out ...
16
votes
2answers
2k views

Knights and knaves in a foreign language

You die and ascend to heaven, there is a knight (truth-teller), a knave (pure liar) and a joker (random) sitting on a cloud - they all look the same. In order to gain entry you must determine their ...
13
votes
7answers
2k views

Faulty computers

You have $99$ computers in a LAN room, and you know that at least $50$ are working. The others can be faulty. The only thing you are allowed to do is to ask computer $i$ the question "Is computer $j$ ...
17
votes
11answers
13k views

Knight, Knave and Joker puzzle

Here is an excellent puzzle with 3 types of characters: You are lost in a town and meet 3 men. You somehow (God told you) know that they are Knight, Knave and Joker. Knight always tells truth, ...
5
votes
2answers
2k views

The 3 Talking Hats

There are 3 talking hats on the table. Each can ask 2 questions, to either hat. 1 of them speaks only truth. 1 speaks only lies. 1 can speak only when spoken to, he will speak at random. YOU know who'...
4
votes
5answers
990 views

About Knights and Knaves and their consistency

On an Island of Knights and Knaves (where Knights always tell the truth and Knaves always lie), a Knight will never contradict himself unless some true fact changes. I was wondering: can a Knave ...
3
votes
3answers
2k views

About the island of Knights and Knaves

On one of the Islands of Knights and Knaves you land for the purposes of an anthropological survey. The Island has Knights who always tell the truth ( if they know enough information regarding a ...
112
votes
16answers
1.3m views

Two doors with two guards - one lies, one tells the truth

You are a prisoner in a room with 2 doors and 2 guards. One of the doors will guide you to freedom and behind the other is a hangman–you don't know which is which. One of the guards always tells the ...
16
votes
1answer
2k views

Is this a new kind of liar puzzle?

I would like to ask if anyone has seen elsewhere this variation on the standard truth tellers/liars kind of puzzle. In the usual repertoire it is assumed that every person questioned knows the answer ...
11
votes
9answers
15k views

Survive from death by asking the right question from trolls [duplicate]

You are in the intersection of two roads, there is a troll in the beginning of each road. One of them is liar (always lies), and one of them always tells the truth. One of the roads, ends to your ...
18
votes
3answers
3k views

Knights and jokers

There are $N$ men. $K$ of them are knights, $M$ of them are jokers. $N$ is known, $K$ and $M$ are unknown. You know that: $K + M = N$, $K \gt M$, $M \ge 1$, $N$ is odd. Knights always tell the truth, ...

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