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.
276
questions
0
votes
2answers
145 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 ...
0
votes
1answer
290 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
...
1
vote
1answer
185 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 ...
5
votes
2answers
165 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.
...
-6
votes
1answer
99 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
...
7
votes
1answer
200 views
The Serpent-Tail
After defeating the octangular spirits, you find yourself needing some laundry powder. However, you can't find any at your usual shop, and so you have to ask one of the employees, who happens to be a ...
4
votes
1answer
215 views
The Eight Spirits
After your ordeal with the enterpeton, you need the toilet. Unfortunately, your ability to urinate has been stolen by one of the octangular spirits, a set of spirits that follow strange rules. The ...
1
vote
2answers
226 views
Organs of the Enterpeton
An enterpeton has arrived at the bathhouse. Enterpetons are strange reptiles with exposed organs. Four of these organs can answer questions, and follow certain rules. These organs are: the heart, ...
0
votes
2answers
145 views
The Rainbow Serpents
At your bathhouse job, you encounter a pair of rainbow serpents, each having two heads, hiding behind a wide pillar. They seem to be bent around the pillar with a head from each serpent visible on ...
3
votes
2answers
255 views
Cursed Knights and Knaves
You are packing up after a week-long stay at the Verity Inn. You came here, to Truth Town, to visit your friend but now it's time to go home. You feel in good spirits as you pack your bags. As you are ...
1
vote
3answers
498 views
The Third Hardest Logic Puzzle in the World
This puzzle is heavily derived from the Second Hardest Logic Puzzle in the World, which I also created. The current puzzle and the aforementioned are not identical, however.
You have 5 guards: one ...
-3
votes
1answer
243 views
How can a liar and a truthteller prove their identities? [closed]
You come across two people. One is a liar who always lies and the other is a truthteller who always tell the truth. You don't know who is who though.
Both these people are allowed to say one sentence ...
31
votes
2answers
3k 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 ...
6
votes
0answers
229 views
Trying to find a 2020 puzzle hunt with a puzzle based on Among Us
I am trying to find a puzzle hunt that I believe was held in 2020. It contained a puzzle based on the game Among Us with 26 characters, and you had to decide who were the imposters. The imposters all ...
8
votes
3answers
542 views
Which Demon Spoke?
While wandering, you encounter a pond, in which two demons are bathing. One is labelled 'honest', meaning they always tell the truth, and the other is labelled 'liar', which means they always lie. As ...
1
vote
1answer
459 views
Knight or Knave
On the island of knights and knaves (where knights always tell the truth and knaves lie), you meet two islanders named Penny and Quinru.
Penny: Both Quinru and I are knaves!
Who is a knight and who ...
11
votes
4answers
2k views
Who is the liar (Number of liars)?
There are 5 people. Each one can be lying or telling the truth, and they can't switch. Below, each person tells us how many liars exist in the group.
There are at least 3 liars.
There are at least 2 ...
7
votes
3answers
462 views
Can you find and capture a shapeshifter?
A town was invaded by aliens, and some of its residents were kidnapped and replaced by shapeshifters. You're tasked with capturing one of the shapeshifters. Here's the setup:
There are 7 residents of ...
4
votes
1answer
287 views
Trapped in an escape room with 2 liars
You are in a room, with 6 people. 2 of them are liars. The room has a code pad. The people say:
People
What they say
Keith
The first and last digit are the same number and are not used anywhere else ...
10
votes
3answers
450 views
We have captured 5 spies. Their names are A, B, C, D, and E
This is a variant of the puzzle here.
We have captured 5 spies belonging to a secret organization. Their identities are unknown; we only know them by their codenames A, B, C, D, and E. After thorough ...
-2
votes
1answer
103 views
Is asking your one question by doing an action an answer to the two doors, two guards puzzle? [closed]
Is asking your one question while doing an action an answer to the two doors, two guards puzzle? Example: You ask your one question by moving towards any door. Only the true guard will continue to ...
-2
votes
2answers
189 views
How many children wear a yellow t-shirt?
The puzzle is as follows:
In a certain kindergarten there are 23 children. Some of them wear a
green t-shirt, others a yellow t-shirt and others blue t-shirt. A tv
reporter who was on the site doing ...
1
vote
1answer
138 views
Knight can't answer about joker
If you ask a knight (True) about a Joker's answer (random), then she can't answer because she doesn't know?
Does this give a NaN response or is it not allowed?
I looked at similar questions and couldn'...
5
votes
2answers
515 views
The wrapping machines of Santa
Christmas is coming and Santa is working hard to wrap all the presents until the 24th of December.
He has six wrapping machines: A, B, C, D, E and F, that work $24/7$ all at the same time. But the ...
1
vote
2answers
153 views
Guess the hat colors - Riddle 6
And for today, a new original hat guessing puzzle!
CHALLENGE: Guess the hats of the 4 prisoners.
SPECIAL RULE: One of the prisoners is lying
DESCRIPTION: Each one can see the hats that are in front ...
9
votes
2answers
209 views
Great puzzle makers of yore: #1, Martin Hollis: "The Poacher's Funeral"
When Peter the Poacher died, his six direct descendants all came to the funeral, each being a son, grandson or great-grandson of the old reprobate. The "Chippings Post" sent a man to compile ...
6
votes
2answers
413 views
2 weird problems I came across
A man accused of murder hires a lawyer who is always believed by the court to be telling the truth. The prosecution's attorney says that if the accused man committed the murder, he had an accomplice. ...
3
votes
2answers
253 views
The ice cream puzzle
I am a new user, and I made this puzzle myself, but I lost the answer key, can anyone solve it so I can make a new one?
The owner of the ' Super Ice Cream' shop was terrified. One of his workers was ...
7
votes
3answers
642 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 ...
10
votes
1answer
228 views
Mirror, mirror on the wall, who's the fairest of us all?
Three evil queens, accompanied by their magic mirrors, go for a girls' night out. At some point of the night they decide to finally settle the eternal question: who's the fairest of them all? Of ...
4
votes
5answers
1k views
One truthteller/liar and one random person
You come across two peculiar aliens: Alice and Bob. You know the following about them:
-Alice is either a "truthteller" (she always tells the truth) or a "liar" (she always lies).
-...
3
votes
1answer
386 views
Murder Mystery Question from an Entrance Exam
Here is a question I've been having some trouble with. I'd love any of your thoughts. It is Question 3 in this entrance exam.
Mr Cadbury was murdered last night.
Exactly one of six suspects is ...
3
votes
3answers
373 views
Vampires, Insanity and Transylvanian Sisters
This is a puzzle from this site: https://medium.com/i-math/vampires-insanity-transylvanian-sisters-88ce3516fd
I thought it was very nice, so I wanted to share it with you. WARNING: the above link ...
10
votes
3answers
675 views
Eight campers and the right path
In the spirit of some of my Raymond Smullyan favorites, here's a relatively hard puzzle from a Dennis Shasha collection of $1988$:
Eight kids and their guide are lost on a forest exactly one hour ...
4
votes
6answers
1k views
Who broke the window? [closed]
There is a broken window in the house. I asked who broke the window:
Gregory: I was not!
April : I didn’t do it.
August: April was.
June : August says the truth
Two of them said the truth, and two ...
0
votes
3answers
136 views
City of Lies or Truth [duplicate]
Try to solve this one:
You are at an unmarked intersection ... one way is the City of Lies and another way is the City of Truth.
Citizens of the City of Lies always lie.
Citizens of the City of ...
4
votes
2answers
2k views
Two Truths and a Lie: a logic puzzle
I'm crafting an answer to the game Two Truths and a Lie: each person playing the game says three statements (usually about themselves, though I'm ignoring that requirement for this), two of which are ...
6
votes
1answer
259 views
Question which is sort of puzzle from mathematics Exam
I am self studying and trying questions of quantitative aptitude in my mathematics exam and I am unable to solve this problem.
Of three persons $A$, $B$ and $C$, one always lies while the others ...
20
votes
4answers
2k views
Boys and girls in a circle
There are $28$ students in a class, and each of them are either boy or girl. They sit in a circle, and claim that “The two people next to me are of different gender than each other.” It's known that ...
8
votes
1answer
467 views
Sane and crazy persons
I have found this puzzle on internet.
40 persons sit in a round table . All of them are either sane or crazy. When you ask a person "is the person sitting to your right sane or crazy?" a sane person ...
9
votes
3answers
680 views
Knight and Knaves Castle
I was pretty bored in the lockdown so I thought up a mathematics puzzle, which I haven's solved yet, so the community can solve together.
Let $n>1$ be a positive integer. There is a square castle ...
5
votes
3answers
397 views
Shocks and guesses
The Liar, the Random and Truth teller were captured and brainwashed to forget whether they always lie or tell truth or randomly answer.Everyone is handcuffed to a chair and gagged with gray, white and ...
1
vote
1answer
189 views
The Lying Brothers
The little town of Stackville is exactly like hundreds of other little communities in every respect but one. Its scenery, its stores, its churches all have their counterparts at every crossroads in ...
30
votes
5answers
2k views
How many spots do these frogs have?
You are approached by 5 spotted frogs who appear to be venomous, to avoid getting bitten by them, you must find out how many spots they have. The frogs with an even number of spots always tell the ...
3
votes
1answer
205 views
Fork in the road problem - with a single person
You walk to a fork from where two roads come out - one leading to a post office and the other to a university.
You want to go to the university, but do not know which road would lead you to it. A ...
8
votes
1answer
227 views
Two persons and one question "Is the shaman honest". Which one of them is the shaman?
An anthropologist arrived to the shaman's den where there were two persons, one with a green hat and one with a blue hat. One of the shaman's students had said that there was a Star Predictor with the ...
6
votes
2answers
490 views
Smullyan Logic Puzzle about Nelson Goodman Principle - Knights and Knaves
In Smullyan's "Logical Labyrinths" there is the following problem 1.11:
...
8
votes
1answer
335 views
Constructing an island according to rules in Smullyan's "What is the Name of this Book"
I've recently finished dropping my jaw at Raymond Smullyan's "What is the Name of this Book," and the section on Gödel's incompleteness theorem, involving islands of knights (truthers) and knaves (...
2
votes
1answer
468 views
What is the smallest number of lies needed to solve a Dragon Joust puzzle?
I recently watched this video which presents a deduction "riddle" about dragon jousting. The rules for the puzzle (from the video) are as follows:
After centuries of war, the world’s ...
4
votes
8answers
735 views
Two doors, two guards, and two keys
Table of contents
Introduction - read about where the puzzle comes from.
The puzzle - read the puzzle itself.
Warming up - read about solutions to a simpler variation of the puzzle.
Introduction
(...
