Linked Questions

0 votes
2 answers

Hunting for treasure in 1-d grid [duplicate]

In a castle, there are N rooms in a line. Each room has a door to the two neighbouring rooms (or the one neighbouring room, for the rooms at either end). A treasure is hidden in one of the rooms. ...
nz_21's user avatar
  • 101
2 votes
0 answers

An elusive hotel guest [duplicate]

From Building Thinking Classrooms in Mathematics: An eccentric woman has booked three adjacent and adjoining hotel rooms. When she checks in, she tells the receptionist that if he needs her, she will ...
Ephraim's user avatar
  • 121
31 votes
10 answers

One prize, infinitely many choices

Having reached the final stage of a game show, you face an endless row of doors labelled $1$, $2$, $3$, ... The game show host has selected a whole dollar amount, and has put this exact amount as a ...
Johannes's user avatar
  • 4,400
26 votes
6 answers

Maze Solving Robot

Archie the archeologist has discovered an Egyptian temple, and plans to send in a robot to explore it. He uncovered the ancient engineers' papyruses which explain almost everything about the temple's ...
Mike Earnest's user avatar
  • 32.5k
18 votes
4 answers

Catching a Cat on an infinite Line

Upon entering a (very) large room, you are faced with an infinite line of cardboard boxes that are labeled, in order, by the nonnegative integers. In one of these boxes, a cat is hiding, but you do ...
Tim Seifert's user avatar
  • 1,743
12 votes
3 answers

Can you catch the thief?

This was a puzzle I recalled from university a couple of years back. I don't know what the original puzzle is but if someone knows it, please let me know so I can credit the source. You are a police ...
pepijno's user avatar
  • 223
10 votes
2 answers

Save the person in 14 moves on a cross

A person was trapped in a building, and you have to save him. You are a police officer and you will arrive at the building at 7 o'clock in the morning. The building looks like this: Every 2 minutes, ...
Matheinstein's user avatar
15 votes
1 answer

Hunter chasing a fox on a graph

This is a variant of the sleeping princess puzzle. There are fifteen foxholes, connected by underground tunnels as shown below. A fox is sleeping in one of them. Every day, a hunter checks one of ...
Mike Earnest's user avatar
  • 32.5k
6 votes
5 answers

A mouse, Two mousetraps, Eight houses

You are chasing a mouse living in a row of eight houses. Every night the mouse moves from the house it is in, to an adjacent house, and stays there the whole day. Apart from this, you have no a-priori ...
Johannes's user avatar
  • 4,400
9 votes
2 answers

A Strange Box of Buttons

Your friend has given you a very unusual birthday present. It is a round box, and inside the lid are $n$ buttons equally spaced in a circle. The box functions like this; you can press two buttons, ...
TheGreatEscaper's user avatar
13 votes
1 answer

Hiding Cat Puzzle on a Grid

The Youtube channel MindYourDecisions posted a video about the "Hiding Cat Puzzle". In the puzzle, you have a line of five boxes, one of which contains a cat. You don't know where the cat is, and your ...
Riley's user avatar
  • 14.4k
5 votes
1 answer

Two knights searching for a princess in a castle

There is a castle with rooms arranged in a 3x3 square grid. The princess living in the castle sleeps in a different room each night, but always one adjacent to the one in which she slept on the ...
Dmitry Kamenetsky's user avatar
2 votes
1 answer

How can the princess escape the prince?

This is the story of the sister of the princess in this puzzle. I will shamelessly copy-paste some parts of this post. I have no reference to give for this version as I adapted a Computer Science ...
Nathaniel's user avatar
  • 193