Questions tagged [liars]

Puzzles that focus on getting information from truth-tellers (who never lie), liars (who always lie), and Jokers (who answer at random).

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7
votes
9answers
1k views

Five beautiful ladies

So there are five beautiful ladies whose faces are veiled. You can distinguish them well as they have written their (correct) names Alice, Betty, Cindy, Diana and Emily on their T-shirts. You know ...
4
votes
3answers
762 views

Identify A B & C using the least number of directed logic statements (Knights, Knaves, Normals)

Here is a puzzle I have not yet been able to solve: There are three people A, B and C who know each others identity. You may pick A, B or C show him a logic statement (truth functional compounds ...
6
votes
3answers
2k views

Another village of liars and truth-tellers

There are two kinds of people living in a village: those who always lie (liars) and those who always tell the truth (truth-tellers). Everybody knows each other in the village and therefore knows ...
14
votes
3answers
1k views

Truths, Lies, and Xors

Rusty is a member of the highly secretive Logician's guild. After years of grueling trials, he is now finally allowed to meet the three leaders of the guild. Their names are Truman, Lyle and Xavier, ...
7
votes
1answer
552 views

Dinosaurs and Elephants

There are two species living in the land of Puzzling: elephants and dinosaurs. Elephants always tell the truth when talking about an elephant, but always lie when talking about a dinosaur. ...
6
votes
1answer
2k views

Who is the liar among A,B,C?

Of three persons A, B and C, one always lies while the other two always speak the truth. C asked A: "Do you always speak the truth, yes or no?" A said something that C could not understand. So C ...
12
votes
5answers
1k views

Meta Knights and Knaves Puzzle with Hats

I landed on the island of Knights and Knaves where Knights always tell the truth and Knaves always lie. I set out to find their two leaders, Raymond and Martin and I really wanted to talk with Martin....
7
votes
4answers
756 views

Born to lie, to live, to die

There is a race which has a truth gene. It consists of 3 alleles, namely T, F and O. A person inherits one allele from each of his parents, hence he/she has always exactly two alleles. For example, if ...
3
votes
3answers
827 views

Similar to knight/knave puzzle: Insane asylum

Premise: These are like the knight-knave puzzles; only now we are visiting insane asylums, where there are only patients and doctors. Moreover, each of them are either insane or sane. Sane inhabitants ...
22
votes
2answers
5k views

The village of the liars and truth-tellers

I read this puzzle in an Italian newspaper some days ago. It reported it was asked at one of the latest Mathematical Olympiads. It's not difficult, but it requires some logical thinking. I'm posting ...
-2
votes
1answer
388 views

The true and false babies [duplicate]

There are two babies, the truth baby and the false baby. The truth baby will respond to any question with a true answer, and the false baby will respond to any question with a false answer. The ...
7
votes
7answers
4k views

Who is the horse thief?

Recently there had been horses missing from the stables. The owner barely noticed, until his horse was stolen. He has four suspects but was unable to identify the guilty one. They each gave three ...
29
votes
1answer
3k views

Murdered down the Rabbit Hole (a long logic puzzle)

Backstory Disaster has struck for Leporidae throughout the fantasy realm -- a mass carrot famine has wreaked havoc upon all existences but our own. Because of this, 25 of the leading fantasy bunnies, ...
4
votes
3answers
492 views

Finding a knight with a few jokers thrown in

Much like this other time, you are lost in town and come across a line of $j$ jokers and $k$ knights. You don't know who is who, but they all know the identities of each other. A knight always tells ...
31
votes
12answers
6k views

Knights, Knaves and Normals

In the kingdom of Boolistan, every inhabitant is either a Knight, Knave or Normal. Knights can only make true statements, Knaves can only lie, and Normals must either tell the truth or lie. Warmup: ...
10
votes
1answer
877 views

Who stole my laptop?

It’s obvious that one of my “friends” was lying to me back in March this year. Someone who knew I’d be gone stole my $1,500 laptop and my crappy old broken microwave (I probably won’t ask for that one ...
3
votes
1answer
5k views

Which is the door to heaven [duplicate]

After living a peaceful and calm life, you die a painless death. Your spirit starts ascending into heaven when suddenly you are approaching two doors. Both doors are completely identical and there is ...
2
votes
8answers
3k views

A few simple riddles to get your brain going [closed]

Here are a couple of riddles for you. 1.) Where does twelve plus two equal two? 2.) A man walks up to you and says "If you tell a lie I will stab you with a knife. If you tell the truth I will shoot ...
22
votes
6answers
10k views

Which teacher is the murderer?

In the first day of a new class semester, a student was murdered inside the classroom. No witnesses, no murder weapon, and no evidence. The police got four teachers as possible suspects, but they all ...
13
votes
2answers
3k views

The broken window

A window was broken in my house and I need to find out who did it, can you guys help me? When asked who did it my friends replied with the following in order starting with 1: "I didn't do it" "1 is ...
-1
votes
3answers
197 views

Who is the liar?

Three friends are playing a game of memory, there are a total of 20 cards with 10 card pairs. They try to make the most pairs in a row, after everyone had a turn they make the following statements: ...
11
votes
2answers
556 views

Liar Puzzle with Stack Exchange Users

You are in a chatroom with three Stack Exchange users. They are a Spambot, a Trusted User, and a Moderator, but you don't know who is who; the chatroom only displays their names (user314, user2718, ...
3
votes
2answers
582 views

How does a common man solve impossibly hard truthteller/falsifier questions?

How does one solve the World's hardest puzzle, and other questions of the type? Is there a proper approach to such a question, or does one just have to be incredibly smart to do so? And here's an ...
1
vote
2answers
1k views

What color is the statue? [duplicate]

This question has been tagged as duplicate of Two doors with two guards. What makes this questions different: Let me state the obvious about this question: you meet one islander. you ask one ...
-3
votes
1answer
491 views

3 suspects Logic Puzzle [duplicate]

The following puzzle was posted here, but providing answers to the puzzle was closed without a correct and complete answer being provided: An inspector knows that exactly one of 3 suspects committed ...
20
votes
8answers
10k views

Logic puzzle - 3 suspects

An inspector knows that exactly one of 3 suspects committed a crime, and interviews them to find out which. Each person lies one time, and tells the truth the other time. A says: I did not do it. B ...
25
votes
4answers
8k views

King Octopus and Servants Puzzle

Puzzle: King Octopus has servants with six, seven, or eight legs. The servants with seven legs always lie, but the servants with either six or eight legs always say the truth. One day, 4 servants ...
2
votes
2answers
3k views

Nine togglers, one truth teller, and only a single question

You are standing in front of ten people, one of which is a truth-teller while the other nine are togglers . (A toggler is a person who toggles between the-truth and the-lie for every question asked.) ...
28
votes
13answers
93k views

Three Doors, One Truth-Teller, One Question

You are in a prison. There are 3 doors, and a ghost standing in the middle of the prison. He says one of the doors is the way to freedom while the other two lead to death. You get to ask only one ...
11
votes
3answers
2k views

The 10 Logicians

There are two types of logicians: knights and knaves. Knights will always give a statement that is true whereas knaves will always give a statement that is false. After listening in on a conversation ...
0
votes
0answers
167 views

3 Gods Logic Puzzle [duplicate]

This logic puzzle can be found on the web so NO GOOGLING! You walk up to three gods. One always tells the truth, one always lies, and one randomly decides to tell the truth or to lie and does what ...
11
votes
2answers
763 views

The Three Seers

Your kingdom has been aided, for as long as anyone remembers, by three great seers. These seers are all-knowing and will truthfully answer one question of any person that seeks them. This question ...
5
votes
1answer
808 views

Kill the jokers! - Part 2

The famous and ruthless explorer Wyoming Wilbert reports in the third part of his memoires that he once visited an island inhabited by jokers and truth tellers. Truth tellers always tell the truth, ...
5
votes
3answers
790 views

Knights and Knaves in the Wild West

Late at night at a bar in the Wild West only two cowboys from out of town are left, playing poker with the barkeeper. One of them cheats, so another throws over the table and they have a fistfight (...
25
votes
11answers
6k views

Kill the jokers! - Part 1

The famous and ruthless explorer Wyoming Wilbert reports in one of his books that he once visited an island inhabited by jokers and truth tellers. Truth tellers always tell the truth, whereas jokers ...
17
votes
1answer
2k views

The Pirates of Beal Isle - very long logic grid puzzle

Story Let me tell ye a tale: Somewhere northeast o' the Bahamas there be a tiny scrap o' rocks stickin' up out o' the sea known as Beal Island. It be a barren, rocky place, and no man ever called it ...
18
votes
4answers
2k views

Past, Present and Future

There are 3 gods, named Past, Present and Future, who all look identical. They sit in a throne room, with one in the middle, the others on the right and left. You are allowed to ask them a series of ...
3
votes
1answer
347 views

Ultimate family dart game

A family of 3 - a father, mother and son - are practising on a dart board. It has 3 shapes - a triangle, a circle and a square - on it. Scoring is as follows: Intersection of all 3 shapes - 5 points ...
17
votes
3answers
2k views

Lies, damned lies, and statistics

A (hopefully) new variant on the Knights & Knaves problem. On the island of D'Israel, the inhabitants fall into three types: Liars, Damned Liars, and Statisticians. They are visually ...
6
votes
5answers
1k views

Over the Bridge, If You Dare [closed]

A young man walks through the forest. He comes to a bridge. In front of the bridge is a large man carrying an axe. The man says, "If you want to cross this bridge, you must tell me something. If ...
5
votes
1answer
637 views

Schizoid twin brothers

There are two identical twin brothers. The first one is honest, but he lies in his schizophrenic situations. The second one is well-known liar, but he tells the truth when he gets one of his ...
4
votes
2answers
920 views

Island inhabitants: Who lies and who tells the truth? [duplicate]

On some island, the population is split into native people and into outlanders. There are more natives than outlanders. Someone with extreme logical and mathematical thinking wants to know who are ...
6
votes
2answers
501 views

How many knights

In a room are 13 men, who are either Knights (truth tellers) or Knaves (lie tellers). the first man looks around and says "The number of knights in this room is no greater than one" the second man ...
7
votes
6answers
2k views

Knights and knaves at a party

On an island, all inhabitants are either knights or knaves. Knights always tell the truth and knaves always lie. No tribe is gender related and some people marry into a different tribe. When I ...
21
votes
5answers
3k 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
2k 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 ...
0
votes
3answers
2k 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. ...
46
votes
10answers
15k 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 ...
10
votes
3answers
12k 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 ...