218 views

### 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. ...
• 101
90 views

### 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 ...
• 121
3k views

### 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 ...
• 4,400
5k views

### 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 ...
• 32.5k
2k views

### 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 ...
• 1,743
2k views

### 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 ...
• 223
937 views

### 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, ...
• 473
1k views

### 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 ...
• 32.5k
1k views

### 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 ...
• 4,400
797 views

### 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, ...
1k views

### 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 ...
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438 views

### 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 ...
• 36.2k