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223
votes
8answers
25k views

My prefix is food, my suffix is rude

I thought of this riddle myself. Feedback is appreciated. My prefix is food. My suffix is rude. My infix comes in rounds. I keep you off the ground. What am I?
57
votes
4answers
9k views

Interview Question or Pathbreaking puzzle

I thought this changes the way series of numbers are looked at 1 1 1 2 1 1 2 1 1 Write down the next three lines
45
votes
2answers
4k views

Vowelburger™ Riddle

(A new kind of riddle) I ordered 5 Vowelburgers™ with buns and meat only - help me identify each one from the description on the menu! Meat Vowelburger™ A weak E cyst I succeed O secured Y ...
112
votes
16answers
1.2m views

Two doors with two guards - one lies, one tells the truth

You are a prisoner in a room with 2 doors and 2 guards. One of the doors will guide you to freedom and behind the other is a hangman–you don't know which is which. One of the guards always tells the ...
62
votes
8answers
110k views

Twelve balls and a scale

You are given twelve identical-looking balls and a two-sided scale. One of the balls is of a different weight, although you don't know whether it's lighter or heavier. How can you use just three ...
94
votes
1answer
12k views

Cryptic Clue Guide

This post is not a puzzle. There is nothing puzzly hidden inside it or the self-answer, posted at the same time. What exactly is a cryptic crossword clue, and how do I write one?
73
votes
1answer
6k views

Word Riddle - you love me or you hate me

With two I’m affirmative With three I’m respectful With four I’m more respectful With all five I’m either loved or hated But when I’m loved, I kill; and when I’m hated, I may save lives.
34
votes
2answers
3k views

Introducing Gladys, an intrepid globetrotter

Gladys has always led an active life full of adventure. As a retiree, she has a lot of free time on her hands and loves to spend it on her two favourite pastimes – travelling and crossword ...
188
votes
25answers
88k views

In the 100 blue eyes problem - why is the oracle necessary?

The riddle Randall Munroe (of xkcd fame) has, a bit hidden on his site, a logic puzzle: A group of people with assorted eye colors live on an island. They are all perfect logicians -- if a ...
31
votes
1answer
3k views

The first Density™ Puzzle!

Welcome to the very first puzzle in a new series! It's all about (hopefully) exploring new ways of creating puzzles, as densely as possible. If you'd like to create your own Density™ puzzle, the ...
22
votes
2answers
9k views

A general solution to the decanting problem? (aka jug-pouring, water-pouring)

Take a look at these two questions: - A Set of Water Jug Challenges - Pouring problem Now I'm asking for a generalised solution to that problem. I define the problem as follows: You are required ...
33
votes
2answers
3k views

Determine the algorithm

So I was given this puzzle quite some time ago and just thought it would make a nice addition to this site: Your task is to determine the method how the result is determined from the given number. A ...
44
votes
6answers
7k views

Burning ropes as timers

You have 2 identical ropes which burn at a specific rate, and an unlimited supply of matches. When you light one end of a rope, the fire will take exactly 1 hour to travel to the other end of the rope....
36
votes
4answers
19k views

Oh, it is greater than God!

What is greater than God, worse than evil, The poor have it, the rich require it, And if you eat it, you die? What is it?
23
votes
2answers
12k views

Coin weighing problem

You are given ten stacks of golden coins, each stack consisting of ten coins and a digital scale with arbitrary precision. You know that all stacks of coins are made from gold, weighing 10 grams per ...
20
votes
5answers
6k views

N logicians wearing hats of N colors

N logicians are wearing hats which can be of N different colors (each hat has one color; there can be multiple hats with the same color). Each logician can see the colors of all hats except his own. ...
45
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 ...
28
votes
7answers
14k views

The most words that can be made by successively adding one letter to the original word? [closed]

What is the largest number of words that can be made by just adding one letter to the original word, where each iteration is a meaningful word? E.g. ...
26
votes
2answers
2k views

Where has the last dollar gone?

Lately I have found different versions of this puzzle, I was wondering if it has a name or belongs to a specific kind, so that I can understand it better. Here it is: Peter got \$10 from his father,...
44
votes
6answers
32k 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 purple ...
45
votes
2answers
4k views

Four-words (----||||)

Four-words : My first is indivisible , but not really. My second is a cloak worn by men , but in ancient Rome. My third is a cruel wicked person , but not a human. My fourth is about 20 quires , but ...
8
votes
3answers
641 views

Tiling rectangles with F pentomino plus rectangles

Inspired by Polyomino Z pentomino and rectangle packing into rectangle Also in this series: Tiling rectangles with N pentomino plus rectangles Tiling rectangles with T pentomino plus rectangles ...
114
votes
6answers
27k views

100 Prisoners' Names in Boxes

Names in Boxes The names of 100 prisoners are placed in 100 wooden boxes, one name to a box, and the boxes are lined up on a table in a room. One by one, the prisoners are led into the room; each may ...
14
votes
3answers
1k views

Twelve Labours - Prologue

This puzzle serves to introduce the ‘Twelve Labours’ series of puzzles. Its solution is standalone and does not contribute to the meta-puzzle at the series end. “Wake up, wake up, wake up! What are ...
15
votes
2answers
13k views

Riddle of the Unwanted Present

The one who made it didn't want it The one who bought it didn't need it The one who received it didn't wish for it The one who used it never saw it What was it?
-5
votes
2answers
4k views

The Security to the Party [closed]

A party is being held at a local mansion. The host is very rich and his success is because of one thing ~ his famous recipe for Spaghetti! The only guests that may attend are people the host knows ...
14
votes
1answer
644 views

The Blind Killer - a new series! SS#1

An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus" Other puzzles in this series Welcome to a new sudoku series! This series will run for the duration of the current Fortnightly ...
13
votes
2answers
947 views

Piece de Resistance - Introduction & Ace and A's

OP's Words This puzzle is part of the "Piece de Resistance" series. Read the following section for the storyAce Two Three Four Five ... Hey guys (and gals), I have worked on this for weeks, took me ...
9
votes
1answer
667 views

Living the traveller’s dream

Dear Puzzling, How have you been? I'm excited to tell you about my new trip. For the next three months or so, I will be visiting a total of 65 exotic destinations. I’m so happy to be travelling again! ...
79
votes
5answers
16k views

What characteristics of a ciphertext can be indicators of a particular cipher?

If I have a ciphertext, what information about the probable ciphers used can I infer from the ciphertext itself? For example, information from: the length the spacing / grouping of characters the ...
71
votes
28answers
18k views

You have one question to tell whether the number I'm thinking of is 1, 2, or 3

This is an interesting puzzle which was passed to me by a friend some time ago. I do know the answer, but will refrain from self-answering on this to see where it goes. I'm thinking of a number: 1, 2,...
22
votes
1answer
3k views

How do I tell the children's ages?

My friend once told me a logic puzzle along the lines of: A student asks a teacher what the ages of the teacher's three kids are. The teacher said, "the product of their ages is 72, and the sum ...
16
votes
1answer
855 views

Twelve Labours - #01 Nemean Iron

This puzzle is part of the ‘Twelve Labours’ series. Previous instalments can be found here: Prologue Having finally deciphered his mother’s map, Hercules got dressed, wolfed down some breakfast and ...
15
votes
1answer
576 views

Piece de Resistance - Four Dots in a Line

Four - Dots in a Line This puzzle is part of the "Piece de Resistance" series. Go back to Part 1 (Ace) for the story.Ace Two Three Four Five ... Looking for the next challenge, you got rid ...
14
votes
3answers
877 views

Piece de Resistance - Five Flowers with One Missing

Five - Flowers with One Missing This puzzle is part of the "Piece de Resistance" series. Go back to Part 1 (Ace) for the story.Ace Two Three Four Five ... Removing the silver matter, you see ...
12
votes
1answer
695 views

Double feature: Braaains

This puzzle is part 1 of the Double feature series. The series will continue in "Double feature: Russian desman". Rules of Akari (also known as Light Up)1 Insert light bulbs into any ...
13
votes
2answers
512 views

Piece de Resistance - Three Troublesome Toshes

Three - Troublesome Toshes This puzzle is part of the "Piece de Resistance" series. Go back to Part 1 (Ace) for the story.Ace Two Three Four Five ... For the third time you removed the ...
11
votes
2answers
844 views

Piece de Resistance - Two Boxes, Two Boxes of Letters

Two - Boxes, Two Boxes of Letters This puzzle is part of the "Piece de Resistance" series. Go back to Part 1 (Ace) for the story.Ace Two Three Four Five ... Out of Character: Finally, a ...
528
votes
5answers
62k views

A short, brutal riddle

Left alone, I'm a word with five letters. I'm honest and fair, I'll admit. Rearranged, I'm of no use to trains. Again, and I'm an overt place, warm and well lit. What am I?
79
votes
15answers
88k views

A camel transporting bananas

A somewhat well-known puzzle is described as such: You have a pile of 3,000 bananas. You wish to transport them to a place 1,000 miles away on the back of a camel; however, the camel can only carry ...
37
votes
3answers
5k views

Pirates and gold coins

A group of N pirates has come by a chest containing 200 gold coins. Their rules require that the coins be distributed by the following approach. The pirates are ranked from fiercest to meekest and ...
24
votes
6answers
80k views

Make numbers 1 - 30 using the digits 2, 0, 1, 8

It's 2018 so let's repeat last year's challenge with new digits. This is similar to the "Four fours" puzzle, but using the digits 2, 0, 1 and 8. Rules: Use all four digits exactly once Allowed ...
7
votes
2answers
6k views

Techniques to Solve this Sudoku Puzzle

I have a sudoku puzzle seen below that I am trying to solve. I know I can punch this into some sudoku solver and get the answer but I am looking for techniques I can use to solve this. Any advice?
31
votes
1answer
5k views

The hangman game backward

So, @JLee has posted a hangman game (Hangman- No misses left) on SE. I would like to create one too, but let's do it backward - guess what was the question, with only 1 letter missing: fill in an "a"...
25
votes
1answer
2k views

Four is Cosmic!

This is a little puzzle I heard a while back from one of my mathematically inclined friends- I get the sense that it's bounced around a little, so forgive me if you've heard it. There is a sort of ...
34
votes
8answers
6k views

Dinosaur egg drop

Archeologists discover two dinosaur eggs, and you are given the chance to test the durability of these eggs (bad move on their part). Suppose that these eggs will absorb a specific amount of force ...
18
votes
3answers
3k views

Knights and jokers

There are $N$ men. $K$ of them are knights, $M$ of them are jokers. $N$ is known, $K$ and $M$ are unknown. You know that: $K + M = N$, $K \gt M$, $M \ge 1$, $N$ is odd. Knights always tell the truth, ...
14
votes
2answers
1k views

Twelve Labours - #02 Lernaean Hydration

This puzzle is part of the ‘Twelve Labours’ series. Previous instalments can be found here: Prologue | 01 His first labour now complete, Hercules made his way up the street to the storage depot for ...
124
votes
8answers
22k views

The Sheikh dies

The Sheikh dies, leaving behind three sons, 17 camels and the following order: His oldest son shall inherit one in two camels. His middle son shall inherit one in three camels. His youngest son shall ...
88
votes
7answers
22k views

Why does this solution guarantee that the prince knocks on the right door to find the princess?

I found this puzzle online: On the top floor of a castle lives a princess. The floor has 17 bedrooms arranged in a row. Each bedroom has doors connecting to the adjoining bedrooms as well as to the ...

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