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.
326
questions
3
votes
1
answer
144
views
Knights and knaves variations
The knights and knaves puzzle is old, well known and thoroughly solved.
https://en.m.wikipedia.org/wiki/Knights_and_Knaves
In Labyrinth there's a variation, where one of the participants tell us the ...
14
votes
9
answers
3k
views
The thief, liars, and the honest
There are four people: A, B, C, D. One person is a thief, the thief and two other people are lying. The other person is telling the truth. Who is telling the truth?
A: I am not the thief.
B: D is ...
- 187
-6
votes
5
answers
454
views
One always tells truth and the other lies, figure which is which in only n tries
Here's a simpler and finalized version of the puzzle, the previous got messy due to its WIP status.
Enter the hall of the twin oracles.
One of the oracles is true, and its purpose is to always tell ...
- 97
6
votes
4
answers
926
views
Was Humpty Dumpty right?
Raymond Smullyan's What is the Name of This Book? contains a puzzle which I'll paraphrase here:
Of the identical twins Tweedledum and Tweedledee, one of them lies on Mondays, Tuesdays and Wednesdays ...
- 1,367
-6
votes
1
answer
186
views
Beauty, chef and boxer
Sarah, Megan, and Mike all attended a party last night. Sarah is a beauty pageant winner, Megan is a chef, and Mike is a boxer. The host of the party said that one person told a lie during the evening,...
11
votes
1
answer
351
views
An Infinitude of Perfidious Pupils
Here's an original puzzle I created. Enjoy!
A teacher had infinitely many students, and he referred to them by the designations $\text{Student } 0$, $\text{Student } 1$, $\text{Student } 2$, and so on....
- 573
36
votes
2
answers
1k
views
An Infinitude of Deceptive Devourers
Here's an original puzzle by me. I hope you enjoy!
A mother had infinitely many children, with the following names:
$\text{Albert}_1$, $\text{Albert}_2$, $\text{Albert}_3$, … , $\text{Beth}_1$, $\text{...
- 573
10
votes
6
answers
3k
views
Knights and knaves not on an island
On a fictional island there were two types of people: knights who always told the truth, and knaves, who always lied. They got irritated by people asking them so many questions so they all moved to ...
- 5,936
0
votes
0
answers
75
views
Two doors and two guards (variant) [duplicate]
So, I've finished building my "Island of Logic!", where there are a number of puzzles for travellers. So far, I have a bunch of rivers with river craft, wolves, goats, and cabbages; and a ...
- 296
-3
votes
2
answers
212
views
In relation to "the two door riddle," what is which door either guard is guarding logically dependent upon?
Link to the two door riddle: https://nerdist.com/article/how-to-beat-the-labyrinth-two-door-riddle/
Question: In relation to "the two door riddle," what is which door either guard is ...
-1
votes
2
answers
270
views
Solving this "Who committed the murder" puzzle using truth tables or propositional logic
I'm trying to solve a logic problem, and I'm wondering if it can be done using truth tables or propositional logic. The problem goes like this:
Who killed the mouse?
The owl said the hawk did it.
...
- 93
0
votes
1
answer
413
views
Understanding solution for this puzzle where truth-tellers and liars describe game scores
Source (Page 26-28)
Frieda was fond of visiting exotic locations. On her visit to the island of Yippiekaiyay, she was surprised that the natives of the island could be classified into one of two ...
- 111
1
vote
1
answer
225
views
Need help solving the 'Who killed the vole' puzzle - Can you crack the code? [duplicate]
I am hoping to get some help with a puzzle that I've been struggling with. The puzzle is called "Who killed the vole" and it goes like this:
There are four birds - hawk, owl, sparrow, and ...
- 93
3
votes
2
answers
2k
views
Two Doors and a Guard
While trekking through the swamp of Knights and Knaves, you come upon a pair of doorways: One leading out of the swamp, the other leading to your doom. The swamp of Knights and Knaves is a strange ...
- 1,185
1
vote
1
answer
273
views
A Possible Solution to George Boolos' "The Hardest Logic Puzzle Ever"
The full explanation of the puzzle, by George Boolos, can be found here.
Basically, it goes as follows:
Three gods A, B, and C are called, in no particular order, True, False, and Random. True always ...
- 11
11
votes
3
answers
681
views
The Fourth Hardest Logic Puzzle Ever
This is a beautiful variant of "The Hardest Logic Puzzle Ever". I learned it in high school math class a while ago. (I do not know if my teacher invented this variant.) I know the solution ...
- 293
37
votes
3
answers
3k
views
Which gnome is the tallest?
This is a riddle I and some friends came up with. Say I have four gnomes with different heights. They state the following:
Gnome 1: I am the shortest.
Gnome 2: I am neither the tallest nor the ...
- 617
6
votes
1
answer
478
views
The Old Brazen Head
While walking through the forest, on the way to confess to your crush, you come upon an old house. Outside of this house is an old, damaged Brazen Head, with a hastily wired coin-slot appended beside ...
- 1,185
15
votes
4
answers
4k
views
This logic puzzle is impossible!
Rocks always tell the opposite of a statement and Rolls tell the truth.
If I was to tell you the following:
A says C is a roll.
A says there are 2 rocks.
B says they are a roll.
C says they are a ...
- 56.4k
-4
votes
2
answers
181
views
Truths tellers and liars. A short one
On a strange island five people are living.
Of the one half we know: they only speak the truth,
of the other half we know: they only speak lies.
How is that possible?
- 26.8k
7
votes
4
answers
662
views
Get the treasure from an island of knights and a joker
You've learned that there's treasure buried somewhere on a small island, but not exactly where. The island is a perfect circle with a radius of 25 meters. There are 15 islanders there, one of whom is ...
1
vote
2
answers
157
views
Knights and Knaves [closed]
You are visiting an island with two types of people: knights who always tell the
truth and knaves who always lie. From among the thousands of people who live
on the island, you meet six people who ...
- 19
3
votes
2
answers
375
views
A logic puzzle with some lateral thinking
Original puzzle below created by me. The writing is... to be honest, not that good, but it's a puzzle. Focus on the puzzle part.
Your name is John D. Tectif, and you're looking for 4 notorious ...
- 624
1
vote
0
answers
83
views
Truth, error, and random [duplicate]
There are three machines named "truth," "error," and "random" (but you don't know who they are). Among them, "truth" always tells the truth, "error" ...
- 101
1
vote
1
answer
205
views
Find Out Our Numbers (liars and truth-tellers)
You are an adventurer to a distant jungle that the news told you it was full on secrets. But, you could not find anything! So you decided to head home.
When you were almost there, a troll (you ca't ...
- 557
-5
votes
1
answer
304
views
Police Interrogation Puzzle [closed]
I have tried so hard to solve this puzzle. But I cannot get my head around it. I have attempted to eliminate the lies and I have come up with Dave as the criminal. But I do not know if it is the ...
- 1
1
vote
1
answer
189
views
The Truth And Lies Today: Revisited
A man is only capable of telling the truth four hours a day. They are either TTFTT or TFTTT (equiprobable). For the other twenty hours, he lies. All hours between 7pm and 6am are night; 7am and 11am ...
- 557
1
vote
1
answer
201
views
The Truth And Lies Today
Suppose a man only tells the truth three hours a day.
It is the same every week and it is known that the pattern of the truth hours are TFTFT.
(which means he may tell the truth at midnight and 2am ...
- 557
-1
votes
2
answers
680
views
Which day of the week is today (Tuesday, Wednesday, Saturday or Sunday) if one of the statements is false?
Today is neither Sunday nor Wednesday.
Tomorrow is not Sunday or Wednesday.
Yesterday was not Friday.
Monday was not the day before yesterday, neither was Sunday.
Which day of the week is today (...
- 11
4
votes
4
answers
233
views
Constraint Satisfaction Problem: who killed Warren White?
Warren White was found shot dead one morning, police have then investigated who was behind the incident. There were 3 suspects who could be suspects in the incident. That afternoon, the 3 suspects ...
- 41
3
votes
2
answers
423
views
I'm not a robot, I'm not a MONKEY
The city of Roboville has been invaded by robots, monkeys, and dancers, who will dance if the beat's funky. Some of the invaders can be two of them (e.g. both monkeys and robots) and some can be all ...
- 557
0
votes
2
answers
397
views
Is this Among Us logic puzzle possible? [closed]
In 11 Among Us players, some of them are crewmates, who always tell the truth, and imposters, who can either lie or tell the truth. Can you figure out who the imposters are? (There can be any number ...
- 557
5
votes
1
answer
225
views
Sobot or fauxbot?
Through the bustling hallway, you followed your speed-walking, speed-talking brother, who was hoping to submit an article about the upcoming demonstration to his beloved Logic and Philately Semi-...
- 711
4
votes
2
answers
645
views
You are left on a deserted island with 15 trolls
You are left on a deserted island with 15 trolls and you must identify who is who to leave.
A tells the truth (truthful)
B lies (liar)
C always says yes (yes taker)
D always says no (no taker)
E says ...
- 557
4
votes
1
answer
263
views
Thieves for questioning
The police got three thieves when they tried to rob a bank. But the officer wants to give them a chance to get free, so he asks them who is the main brain behind the robbery. The thieves were puzzle ...
- 43
6
votes
7
answers
2k
views
Probability that truth is spoken on Thursdays
A man speaks the truth on only two days a week. The days are the same for each week and they are in the TFT form (TFT = True False True. This means that the days on which he speaks the truth are ...
- 2,818
-3
votes
1
answer
172
views
2 blue eyes 99 red eyes
There are 101 normal people on an island. 2 have blue eyes and the rest have red eyes. The people with red eyes can leave the island. But the people with red eyes always tell the truth and the people ...
- 1,313
4
votes
1
answer
973
views
Puzzle 1.3 from Montague island mysteries
I'm on puzzle 1.3 "The Missing Painting" in the book Montague island mysteries
The Missing Painting
An envelope that was pushed under your door during the night contains
this piece of ...
- 41
8
votes
1
answer
503
views
Identify someone as a truth-teller, liar or toggler with one yes/no question
You are visiting an island and need some information. The island has liars, truth-tellers, and togglers. Critically, togglers alternate truths and lies in their answers. When you meet someone, how can ...
- 89
29
votes
2
answers
3k
views
Liar Wordle - Yet Another Wordle Variant!
In Liar Wordle, standard rules apply except each row contains exactly one clue of the wrong colour. For instance if we consider only the first row the correct colours could be Y-B-B-B-Y and the ...
- 7,444
4
votes
1
answer
247
views
The age of three ladies
Three ladies A, B and C have a discussion, where each lady says the truth twice and lies once.
A: B is two years older than me
B: C is 38 years old
C: A is older than me
B: The age difference between ...
- 11.9k
10
votes
2
answers
446
views
How many times do the magicians' coats change color?
In a small town, there live 110 magicians, who can be identified by their magical color-changing coats. These magical coats turn green whenever the wearer tells the truth, and red whenever the wearer ...
- 111
3
votes
1
answer
259
views
Choose your guardian wisely!
I must issue a word of caution dear traveler. As your journey nears its end, you have one final obstacle to overcome. Ahead lies the gate of the guardians. As you might suspect, the gate is protected ...
- 10.6k
7
votes
9
answers
748
views
The Land of Truth and Lies [closed]
You live in The Land of Truth and Lies, where any of your statements may be inverted in meaning, without prior warning. For example, if you intend to say "You're looking good today", you may ...
- 10.4k
24
votes
11
answers
6k
views
Who robbed the store?
You are investigating a shop robbery. The CCTV footage shows that there was one criminal, but it doesn't show their face. There are 10 suspects and you know that one of them is the criminal. The ...
- 33.2k
0
votes
2
answers
405
views
How many liars were there at the party? [duplicate]
Andy’s birthday party has just been moved up by a week. All the toys in Andy’s room are worried about being replaced by fancy new toys. Sheriff Woody, Andy’s favourite toy, and the others are waiting ...
- 101
-1
votes
1
answer
336
views
A one liner question for marriage to a beautiful girl [closed]
Question: One day I saw an extremely beautiful lady
on this island which consisted of only knights (that always are truthful) and knaves (that always lie) and was immediately smitten with her. I
...
- 121
1
vote
1
answer
276
views
Magicians, Knights and Knaves
My solution for this puzzle did not well match with the book's solution. I thought it would be good to check my argument's reasoning, though you can also propose your own answer.
There is an island ...
- 121
5
votes
2
answers
281
views
Knight-Knave-Normal Meta-Knowledge
A traveller visited one of the islands described by Raymond Smullyan on which all inhabitants are either knights, who always tell the truth, knaves, who always lie, or normals, who can say anything.
...
- 1,367
-7
votes
1
answer
160
views
The Ultimate Liars
At the bathhouse, 27 travellers arrive. According to a book they have brought, each one follows a different one of the following rules:
Traveller
Yes
Unknown
No
Sheep
Y
Y
Y
Knightly Sheep
Y
Y
R
...
- 1,185