# All Questions

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305 views

### A grid where every combination of two colours appears exactly once

Is it possible to paint the cells of a rectangular grid with $K$ different colours such that: No two adjacent (horizontally or vertically) cells have the same colour, and Every combination of two ...
98 views

### A Connect Fano Plane

The Fano plane is the smallest example of a finite projective plane, with 7 points and 7 lines, which has the property that every pair of points lie together on a unique line, and every pair of lines ...
25 views

### The river and the log

I gave the next problem to my students the other day to show them that, if we learn to see our problems in a different new point of view, we may be solving them on a much simpler way. A lumberjack ...
2k views

### Is this a good question for an IQ test?

Once, in a college class of mine, my teacher defied each of us to elaborate a good question for an IQ test. I proposed the following one. Is the option C a correct answer for this question? Please ...
2k views

### When you take away two

I am an odd number. When you take away two, I become even. What am I? Edit: @hexomino got my original answer but I have come up with another valid answer. Edit 2: @QuantumTwinkie got my other ...
159 views

### The broken wheel

In a regular polygon, we can connect six of the vertices to form a convex hexagon with different side lengths. Furthermore the hexagon has the following property:if you connect the 3 pairs of opposite ...
148 views

### Perfect power nim

Let $m,n$ be positive integers. Ann and Ben has $m$ stones, and each of them takes exactly the perfect power of $n$ stones ($n^k$, where $k$ is a nonnegative integer) in order, starting from Ann. Who ...
51 views

### Identifying the missing part of the calculation [closed]

The IQ question is, (39+56)/60% = ?*3 Complete the equation by correctly identifying the missing part of the calculation from the list of options below. where in the book answer is stated as 133/7. I ...
156 views

### Help! My Ring & Post puzzle is stuck

I have a fairly basic Ring and Wooden Post puzzle that I can usually solve. However, at a recent family gathering (pre-Covid); the ring was tangled into a weird spot and I cannot figure it out. Here ...
2k views

### Pythagorean quilts

The King requests Pythagoras to his palace to discuss an important matter. After the usual formal greetings the King asks: - I have been told that you have a marvelous formula about adding squares ...
4k views

### Almost impossible Sudoku like puzzle

I was set a puzzle in my math class. I tried to do it using an equation but it didn't work it looked like a trial and error puzzle so I took it into school and the math teachers couldn't solve it. Is ...
520 views

### Formula One (?) Hard Puzzle

On a website I use to go, one of the writers gave this hard puzzle: What are the meaning of those numbers given they are not Norwegian coordinates. 60.6604211,10.7210713 I have no clue how to solve ...
395 views

### A cowboy rodeo riddle [closed]

First, the cowboy went to the rodeo on Monday. Three days later, he went back home on Friday. Can you solve it?
69 views

### So, you are a horse rider and riding on Friday. The next day, it is Wednesday. How is this possible? [duplicate]

So, you are a horse rider and riding on Friday. The next day, it is Wednesday. How is this possible?
233 views

### A very familiar object

I'm sure you all have held a common retractable, spring-loaded pen at least once, and that many of you have tried to make it jump vertically by first pushing it downward against a table to load the ...
117 views

BEE, DON, EXAMINER, GLOBE, HORNET, RETRIEVER, ROO, STAR, SUN, TERRIER These ten words can be paired up into five pairs according to a certain rule. How?
483 views

So I think I might have been hacked...my Google maps has gone crazy. I tried poking a couple of places in, and it is taking me to the wrong location. When I enter CAYMAN, it tells me it is between the ...
2k views

### I found a puzzle that no-one can solve

I found a puzzle that no-one can solve. I created a law but I was not a lawyer. I lived in a hostile world but found refuge in a hut. Who was I, and can you explain my story? Clue 1 Clue 2
137 views

### A ruff awakening

South West of England Parish Church of St. Barry the Lesser So moving... as the first notes rise up to fill its vaults, the little village chapel seems to come back to life. For months nobody has ...
223 views

### The Eighth Color

For this puzzle I've made, guess what is the missing color. You can't use a computer to find the solution. But once you know you have it, you are allowed to use a computer, mostly to select a RGB ...
90 views

### Cryptography puzzle

The two strings below describe the same English word: 7415963852 1475369963 What word is it? Just for fun! Credits: Hindemburg Melão Jr.
70 views

### How many different words can be formed with the letters AAAABBCCD (not necessarily meaningful words)? [closed]

How many different words can be formed with the letters AAAABBCCD (not necessarily meaningful words)? there are 9 letters(4 As,2 Bs 2 Cs and 1 D)
414 views

### Passing the time

Here in the United States, COVID is now casting a long shadow over our summer. To help pass the time where we should be enjoying our normal summer activities, here's a connect wall to remind us of ...
119 views

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381 views

### This number sequence has entered my life recently

Just recently, I've noticed this sequence of numbers has become a pretty big part of my life. It goes like this: 1, 2, 4, 6, 9, 12 So here's the mystery: What is this sequence? Where do I keep seeing ...
1k views

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99 views

### in the sequence 1,11,21,1112,3112,211213…, what comes next? [duplicate]

find the next number in the sequence 1,11,21,1112,3112,211213,... think about all of the numbers and the number after it it is not 311223 you need think outside the box this is not a math question
478 views

### Colored items in a box

When I looked in an old box of mine I found the following x items with 4 different colors exactly: 5 items that are either blue or brown. 7 items that are either brown or yellow. 5 items that are ...
106 views

### Fill in numbers on the cube … again!

You are given a cube. You are told to fill in each face randomly with some of the numbers $4, 5, 6, ..., 11$, with no repetition. What is the probability that for each two faces that are connected by ...
3k views

### From Puzzling to StackExchange

This is a variation of a game I used to play with my friends in my childhood. You are given a starting word, and using the following operations, you have to reach the target word. The solution that ...
399 views

### MEET @ 9:00 PM TONIGHT

Sarah was a cryptologist for the CIA. One night, as she was getting ready to leave for the day, her supervisor rushed in and handed her and her team a single sheet of paper. "We've got less than ...
2k views

### On visiting a certain place, I wrote a line of poetry. Where was I?

Longest in its kind across the globe Where five of seven meet the shore Here the rights are set in stone To cruise along the world's floor Where am I? Hint 1 Hint 2 Hint 3 Hint 4 Hint 5 Hint 6 ...
479k views

### Crack the lock code

Does any one know how to crack this? I got this as a challenge.
142 views

### What is missing from my aunt's inheritance?

A few days ago my aunt passed away and left her inheritance. I feel like something is missing but I don't know what, she left this music score instead: I can't read the musical notation: can you help ...
170 views

### Obfuscated characters

Hidden in These Numbers, letters, and symbols YOu will find something quite Particular. To solVE: please stAte the name foR Code LIke this ...
516 views

### Time to eat then

Let the picture speak for itself. Only 1 option is correct. Give a clear explanation as to why. So... Which one is it?
447 views

### What game am I?

Can you work out what game I am? (My original puzzle): Head hung low in… (5) - Best card of the deck (3) Written much by peer and shakes, often read for the love it makes (6) - Certainly not pretty ...
1k views

### Glory to Arstotzka—The Glorious Infinite Regiment

There are 7 different medals in the Arstotzkan army, which may be awarded multiple times to indicate glory. For any two distinct collections of medals, one is decisively more glorious than the other. ...
192 views

### Help - I think my computer's broken!

I wrote a little computer program to count letter frequencies. Don't worry you don't need to know anything about computers! Except of course for Googling, Wikipedia, etc. So, for example, the ...
92 views

### This encoded code is the code that encoded the code

This gibberish is the source code of what you use to encode and decode it. I'm curious if anybody can decode it and give me the original source code! I'm placing a decent bounty on this in two days ...
439 views

### Buzzword Bingo Boss Battle!

Two bosses of different companies take turns delivering long speeches. Every speech much “claim” at least one unused square by uttering the corresponding buzzword(s) in the table below. Victory is ...
3k views

### Who is the liar among A,B,C?

Of three persons A, B and C, one always lies while the other two always speak the truth. C asked A: "Do you always speak the truth, yes or no?" A said something that C could not understand. So C ...
48 views

### Island Riddle. - How would you approach this and what is your mentality? [duplicate]

There are 12 people on an island. 11 of the 12 people weigh the exact same. However one of them weighs different(more or less you don't know). You have a seesaw. You can only use the seesaw 3 times. ...
717 views

### Professor Halfbrain's infinite chessboard theorems

After his first set of theorems involving queen-accessibility, Professor Halfbrain started wondering about infinite chessboards rather than just ones with arbitrary large dimensions. He came up with ...
210 views

### Crosswords: Maximum number of words in an n×n grid

What is the maximum number of "words spaces" that can be in an n×n crossword, based on the placement of the shaded squares. Some limitations No word can be less than 3 spaces in length ...
93 views

### Competitive puzzles

Do you know any sort of puzzles that can work in the context of a short competition? In other words, puzzles that have these features: The premise should be fairly simple to follow (but the solution ...
80 views

### Hard Equation 7(x–1)–5(2x+2)=49 [closed]

find x in the problem 7(x–1)–5(2x+2)=49 i tried -32/3 and it did not work use the ORDER OF OPERATIONS X =
132 views

### Cryptic Family Reunion: Any Title I Can Think Of Would Give Away The Theme To Somebody

The answer to this puzzle is a list of ten thematically related words or proper names or phrases. Each of these is clued cryptically, and the theme is to be determined. Since the definition part of a ...