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
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 ...
17
votes
6answers
6k views

A death at a restaurant

You are a mafia leader and because of mysterious recent developments, you had to call the meeting of heads which is happening right now at your's cousin restaurant. The problem is, after the opening ...
35
votes
8answers
7k views

Who committed the crime?

A crime has been carried out by one person, there are 5 suspects. Each suspect is asked under polygraph who they think committed the crime. Their answers are as follows: Terry : It wasn't Carl, It ...
5
votes
2answers
636 views

Telling the truth

Atal said Sonia did it. Sonia said Kumar did it. kumar said George did it. George said that he didn't do it and Laloo confessed that he did it if Atal didn't do it. One of the five of them did it ...
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 ...
17
votes
5answers
3k views

Statements that the deities True and False cannot say

You over exert yourself working on logic puzzles and die of exhaustion. You are awoken by the omniscient deities True and False. True only speaks true statements and False only speaks false statements....
2
votes
3answers
958 views

Puzzle to find one good person [duplicate]

There are 15 people who may lie or say the truth(bad people) and 16 people who will always say the truth(good) . Suppose A- bad person , B-good person and C-bad person, when asked about A, B will say ...
9
votes
4answers
1k views

The two neighbouring islands

A puzzle was asked in a mental ability test. Arstil and Byzinte are two neighbouring islands in a far-off corner of the world. The natives of Arstil (the Arstillians) and the natives of Byzinte (...
5
votes
1answer
409 views

The truth and lie mess

There are two persons with special traits such that : One speaks only lies and no truth on Monday, Tuesday and Wednesday and all truth rest of the week. The other speaks only lies and no truth on ...
14
votes
2answers
2k views

A Race of Liars

You find yourself in a strange land where a race with five participants has just taken place. Each of the runners is a different age, and each either always tells the truth, always lies, or strictly ...
32
votes
9answers
9k views

Which offer is better?

You are to make a statement. Of these two offers you have to choose one; which one is more profitable to you, and why? If the statement is true, you get exactly 10 dollars. If the statement is false,...
14
votes
6answers
3k views

To Tell The Truth

Four friends get together. One tells the truth all the time. One lies all the time. One tells the truth on odd-numbered days and lies on even-numbered days. One tells the truth on even-numbered days ...
5
votes
1answer
489 views

What is the best name for true-tellers, liars and normals

In the world exists a lot of puzzles based on variations of true-tellers, liars and normals (sometimes lies, sometimes not). There are plenty of names for these characters, for example see the ...
10
votes
3answers
1k views

The Expedition Into The Ancient Cave

You are a archeologist and have taken 8 of your students on a expedition trip to a ancient cave to try and find ancient treasure. After you and your team entered the cave, you travel as a group ...
19
votes
3answers
1k views

Edward and the seven imps' Game

Excerpt of “Manipulating the Fabric of Space” “Miscasting translocation spells can have many nasty consequences. The caster’s body could be warped or torn apart, his soul could be separated ...
16
votes
6answers
4k views

99 doors to death!

You wake up in a small locked room of a huge castle. There are 100 doors, numbers 1 to 100, and you are to open one of them. Open the correct door, and the entire castle is yours to keep. Open any of ...
15
votes
2answers
1k views

Town of liars and truth-tellers with eccentric mayor

There is a small town with a strange custom. Residents each own a single pebble, painted blue or red, which they always carry in their pockets. Those with blue pebbles always tell the truth, and those ...
6
votes
3answers
381 views

Democrats and Republicans in a Circle

There are $N$ democrats and $N$ republicans sitting in a circle. Each of these people is either always honest or always deceitful. It is known that the number of honest democrats is the same as the ...
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 ...
21
votes
3answers
3k views

Ten Tricky Mathematicians

Somewhere on the Hyperbolic Plane, you encounter ten mathematicians. You know that some of them always tell the truth while the rest always lie. Each of them knows which of the others tell the truth ...
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 ...
7
votes
1answer
671 views

The Beautiful Ladies' Brothers

The ladies mentioned in Five beautiful ladies have five brothers: Adam, Bob, Charlie, David, and Edward. Three have hazel eyes and are honest; two have lime-colored eyes and always lie. You are ...
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
557 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. ...
7
votes
4answers
758 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 ...
5
votes
1answer
639 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 ...
-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 ...
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.) ...
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 ...
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, ...
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 ...
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 $j$ ...
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 ...
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 ...
4
votes
3answers
494 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: ...
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 ...
4
votes
4answers
845 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 ...
10
votes
1answer
883 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 ...
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 ...
-4
votes
3answers
13k 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 ...
4
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 ...
15
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 ...
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 ...
5
votes
1answer
809 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, ...
11
votes
2answers
557 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, ...
-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: ...
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 ...