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.
61
questions
129
votes
16
answers
1.6m
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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, but the guards do know.
One of the ...
- 5,718
18
votes
3
answers
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, ...
- 16.1k
15
votes
2
answers
3k
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 ...
- 12.8k
19
votes
11
answers
14k
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, ...
- 16.1k
14
votes
7
answers
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 $j$ ...
- 759
10
votes
3
answers
2k
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 ...
- 2,131
22
votes
6
answers
11k
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 ...
- 383
13
votes
4
answers
8k
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. ...
- 457
32
votes
1
answer
4k
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, ...
- 17k
25
votes
12
answers
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 ...
- 11.7k
32
votes
2
answers
4k
views
The Second Hardest Logic Puzzle in the World
This puzzle is an original creation of mine (as far as I know), although other people have solved it before me.
You meet five people: Alice, Bob, Carol, Daniel and Evie. Your aim is to ask yes/no ...
- 795
28
votes
5
answers
1k
views
Council of Magic - a palace of deceptive spellcasters
Council of Magic:
The King of Puzzlington has sent you to a distant palace to gain the aid of the Council of Magic. As your luck would have it though, spellcasters are a tricky sort.
There are 4 ...
- 3,909
26
votes
3
answers
2k
views
A Space Station 13 tricky situation
You are the Captain of the Space Station 13, and everything went bad very quickly. Most of the crew died, and it took you not so long to figure out that some people are not who they're supposed to be (...
- 12.6k
25
votes
4
answers
10k
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 ...
20
votes
8
answers
15k
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 ...
- 209
18
votes
3
answers
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 ...
- 116k
15
votes
2
answers
2k
views
Island of Liars
A king goes to an island, where there are 5823 people who always tell the truth and 8723 who always lie.
The king is a special guest for the party celebrating the year 2053.
At the party, liars and ...
- 395
12
votes
3
answers
1k
views
A Space Station 13 complicated escape
After successfully resolving this tricky situation, you, the Captain of the Space Station 13, have ordered what remains of your crew to gather in the escape shuttle. Accompanied by the Security ...
- 12.6k
11
votes
9
answers
18k
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 ...
- 1,335
10
votes
3
answers
3k
views
Knights and liars
An island is inhabited by both Liars and Knights. Knight always tells the truth and Liar always lies. One day 12 islanders gathered together and issued a few statements. 2 of the islanders said "...
- 125
10
votes
3
answers
25k
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 ...
- 1,015
6
votes
5
answers
698
views
Identify who is who between 3 persons who tell the truth and lie alternately
Dipsy tells the truth in 1 day and lies in the next day alternately.
If today he tell the truth, tomorrow he will lying, 2 days later he will tell the truth, and so on.
Lala tells the truth in 2 ...
- 17.8k
6
votes
4
answers
1k
views
5x5 statement table
Statement table.
3 2 1 4 1
2 3 3 3 3
3 4 6 4 4
2 3 4 4 3
1 1 2 4 3
Above 5x5 table contains numbers.
A number at each cell represent a statement.
x : This ...
- 17.8k
2
votes
4
answers
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 ...
- 5,088
2
votes
2
answers
546
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-...
- 16.1k
1
vote
3
answers
4k
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 ...
- 1,015
36
votes
8
answers
8k
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 ...
- 471
33
votes
23
answers
5k
views
Unfortunately, you died [closed]
Your soul is on its way to the afterlife when suddenly you arrive in a room.
You look around and notice six humanoids staring at you.
You walk toward them and you can suddenly hear them talk between ...
- 9,820
33
votes
10
answers
7k
views
Liar liar pants on fire
Here is an easy and straightforward liar puzzle.
Four people are in a room, stack reader, boboquack, Rand al'Thor and Brent Hackers.
stack reader states that at least 2 of the other 3 are liars.
...
- 9,820
29
votes
5
answers
6k
views
You trolls, get out of my party! [duplicate]
You have invited $2017$ of your acquaintances to a party. But after they all arrive, you come to know from a reliable source that each of your guests is either a troll or a true friend. You don't know ...
- 18.6k
24
votes
4
answers
2k
views
Art Accident at Airport!
There was an accident at the airport! A hanging art installation fell and landed on some passengers. In addition to tearing up all their tickets and mixing up their luggage, six people sustained ...
- 4,599
22
votes
4
answers
7k
views
Who stole the flying car in Hogwarts?
During a trial in a Hogwarts court, Ron claimed that the Flying Ford Anglia car was stolen by Hermione.
Then Hermione and Harry gave testimonies which, for some reason, were not recorded. Later on ...
- 670
18
votes
4
answers
3k
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 ...
- 32.1k
17
votes
2
answers
2k
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 ...
- 10.1k
17
votes
9
answers
4k
views
Three boxes, Four questions, Three times not true, Once the truth
There are 3 boxes, only one of which contains a treasure.
The guardian will only answer you truthfully once, the other three times he will lie.
You may ask 4 YES or NO questions.
Which questions ...
- 281
15
votes
9
answers
3k
views
Find the correct door!
This is my first puzzle but I hope it will work out well and that everyone can enjoy it.
While trying to get out of a dungeon, you arrive in a circular room with 5 doors at equal distances from each ...
- 9,820
15
votes
4
answers
51k
views
Two doors with three guards - one lies, one tells the truth, and one is unreliable
This is an extension of Two doors with two guards - one lies, one tells the truth, but in this situation you are a prisoner in a room with 2 doors and 3 guards. One of the doors will guide you to ...
- 574
13
votes
3
answers
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, ...
- 32.1k
13
votes
2
answers
1k
views
Name the trolls
TL;DR
There are 11 trolls named and you should discover their names by asking yes-or-no questions to them, directing each question to one troll. You must use the minimum possible number of questions.
...
11
votes
8
answers
5k
views
Solve the following knights and knaves problem
A says:
“B is a knave.”
B says:
“A and C are of the same type.”
Knights tell the truth and Knaves lie.
What is C? (i.e. a knight, or a knave?)
- 295
10
votes
1
answer
1k
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 ...
- 377
10
votes
1
answer
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 ...
- 14.4k
9
votes
3
answers
682
views
Council of Magic, 5 years later - more spellcasters, more deception
Council of Magic - 5 Years Later:
Five years ago, you managed to gain the support of the Council of Magic. However, now the King of Puzzlington needs their aid once again. As it worked last time, he ...
- 3,909
8
votes
1
answer
967
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, ...
- 11.7k
8
votes
2
answers
575
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 ...
- 1,342
7
votes
3
answers
670
views
Which of my friends has a birthday today?
I have five close friends, Andrew, Benjamin, Cassie, Danielle and Eric. I know that one of them has a birthday today but I can't remember which.
I asked Andrew who had a birthday today, and he ...
- 3,699
7
votes
3
answers
796
views
One truthteller, one liar, and two randoms - least questions to identify?
I have landed on a new planet and there are 4 people there. One of them is a truth teller and they always speak the truth. The other is a liar and they always lie. The other 2 are random and they ...
- 2,818
7
votes
2
answers
693
views
Liars, truth-tellers and jokers
In a strange village there are three kinds of persons: knights (always telling the truth), knaves (always lying) and jokers (who may either tell the truth or lie).
A, B, C and D live in this village, ...
- 436
7
votes
9
answers
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 ...
- 89
6
votes
4
answers
507
views
A Space Station 13 malfunctioning A.I
Disclaimer: It is not necessary to read the previous puzzle, or the one before even if it continues on the same story. The current puzzle is a different one which can work as a pure standalone. ...
- 12.6k