Linked Questions

60
votes
7answers
10k views

Three mathematicians are forever in Prison

I'm excited to share the following riddle. It was given to me more than two years ago and I finally solved it last summer (after not thinking about it for a long time). In my desperation, I tried to ...
43
votes
6answers
28k views

Hats and Aliens

Here's a neat little puzzle taken from a Google interview question: 10 humans are abducted by aliens; each represents 10% of the entire human population. The aliens give each abductee either a ...
51
votes
4answers
41k views

What is the maximum number of solutions a Sudoku puzzle can have?

I've seen Sudoku puzzles that can be solved two different ways. Referring to a traditional 9x9 grid: Is it possible for a Sudoku puzzle to have more than two solutions? If so, what is the maximum ...
40
votes
4answers
4k views

Which switch goes to which bulb?

You are in a room with three switches, labeled $A$, $B$, and $C$. Initially, each switch is in an off state. In an adjoining room, there are three incandescent light bulbs. Your task is to ...
30
votes
7answers
4k views

How long has the warden been the warden?

Summary: It is your first day in prison serving a literal life-sentence under the supervision of the warden. You are to be kept in solitary confinement with no additional information for the ...
21
votes
3answers
2k views

Don't clear your terminal history

You woke up this morning locked in a room. The only apparent exit is a door with a terminal. On the screen you see the following: ...
11
votes
8answers
1k views

Prison Pizza Party

You are an inmate at Infinity Prison, where prisoners must work together to solve a challenging riddle every day to ensure their very survival. But today is your lucky break; the warden has decided to ...
4
votes
1answer
3k views

The Two Switches

11 prisoners arrive at a jail. But this jail is not an ordinary jail, it's a jail whose Warden despises ignorance and reveres wisdom. So much so, that the Warden is willing to free the group of ...
8
votes
1answer
500 views

One hundred and one hats

You are a prisoner. One day, the Warden summons you and ninety-nine others to see his hat collection. "Bowlers and baseball caps. Stensons and sombreros. One hundred and one headpieces, each unique ...
6
votes
1answer
588 views

How long has the warden been the warden? v2

This is follow up question to How long has the warden been the warden Summary: It is your first day in prison serving a literal life-sentence under the supervision of the warden. You are to be kept ...
7
votes
0answers
231 views

The Switch Riddle [duplicate]

I saw this riddle ealier today on 9GAG (and it's found on multiple news sites), I have found 2 answers with my collegues, but i'm wondering if someone else can solve it. 'One hundred prisoners have ...