instruction stringlengths 15 30k |
|---|
Is this a new kind of liar puzzle? |
i made a program for it, and it's algorithm is to get the number from user, reverse it and do the multiplication, if the reverse and multiplication is equall then print it for you.
here is a C# code:
Console.WriteLine("number from");
int a = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(... |
How many sqares can you draw in given pattern, when each corner of a sqare has to lie in the exact center of one of the 20 colored circles?
![enter image description here][1]
[1]: https://i.stack.imgur.com/ZxzBH.jpg |
Inspired by [this puzzle][1].
You have $n$ shooters having a duel, labeled $1, 2, ... n$. Each shooter has an accuracy of $k_n$, with each $k_n$ some probability between 0 and 1, with $k_1 < k_2 < ... < k_n$. The first shooter is the least accurate, while the last shooter is the most accurate.
The duel works as f... |
Inspired by [this puzzle][1].
You have $n$ shooters having a duel, labeled $1, 2, ... n$. Each shooter has an accuracy of $k_n$, with each $k_n$ some probability in $(0,1]$, with $k_1 < k_2 < ... < k_n$. The first shooter is the least accurate, while the last shooter is the most accurate.
The duel works as follow... |
You are on a rowboat in the middle of a large, perfectly circular lake. On the perimeter of the lake is a monster who wants to eat you, but fortunately, he can't swim. He can run (along the perimeter) exactly $4x$ as fast as you can row, and he will always run towards the closest bit of shore to your boat. If you ca... |
It is possible to escape a monster that is a little more than $4.6$ times faster. Given a monster running at speed $X$ times rowing speed and a lake with radius $R$, you must first row to the circle that is $R/X$ from the centre of the lake by spiralling out while keeping the centre of the lake between you and the mons... |
Three friends enter a quiz-show as a team, the final round of the show is all or nothing, they only get their prize if they can win this round.
Three boxes labelled 1, 2 and 3 are placed in a room, each box has either a white or a black stone in it, with a 50% probability for each.
The friends enter the room in t... |
**Edited:**
OK, so on reflection my original answer shown below in italics was not entirely correct. For n>=4 player n-2 should never pass.
*For n>3
1..n-3 shoot at n
n-2 shoots or passes depending on specific accuracy of duelists n-2, n-1, and n
n-1 shoots at n
n shoots at n-1*
To illustrat... |
**Edited:**
OK, so on reflection my original answer shown below in italics was not entirely correct. For n>=4 player n-2 should never pass.
(**Original non-optimal strategy for n>=4**)... *For n>3
1..n-3 shoot at n
n-2 shoots or passes depending on specific accuracy of duelists n-2, n-1, and n
n-1 sh... |
I need help understanding the solution to the following puzzle:
**Puzzle:** There is a "triangular" duel between the three shooters. Everyone shoots one by one, can shoot once and any person he wants. Smith always hits the target (100%) and shoots last. Brown hits the target 80% of the time and shoots second. Jones ... |
I need help understanding the solution to the following puzzle:
**Puzzle:** There is a "triangular" duel between the three shooters. Everyone shoots one by one, can shoot once and any person he wants. Smith always hits the target (100%) and shoots last. Brown hits the target 80% of the time and shoots second. Jones ... |
I found the explanation of the puzzle by its [original author][1]. The answer is in fact for Jones to shoot into the air until one of the opponents is dead.
The order is kept as per the question, but working with probabilities we need to consider all possible outcomes. Thus, we consider the case where Brown shoots J... |
I'm amazed that, although well known, this problem hasn't been posted yet.
## Monty Hall ##
The story goes like this(from memory):
- You are on a game show.
- The host of the show shows you three doors.
- He tells you that behind one of them, is a new car, and behind the
other two is nothing(sometim... |
You are on a rowboat in the middle of a large, perfectly circular lake. On the perimeter of the lake is a monster who wants to eat you, but fortunately, he can't swim. He can run (along the perimeter) exactly $4\times$ as fast as you can row, and he will always run towards the closest bit of shore to you. If you can... |
Two people, Anne and Bob, each hold an index card. A positive integer is printed on each index card, and these integers are consecutive (i.e. Anne's card may display 8 and Bob's card 7). Anne and Bob are aware of this information, and in addition they each know the number printed on their own card, but _not_ the number... |
Solution guide: http://rubiks.com/uploads/general_content/Rubiks_cube_3x3_solution-en.pdf
I can get to this point pretty reliably now, but when I try the method shown I'm just as likely to go from one or no corners to two yellow corners as I am to go back again the next round. I don't mess up the solved rows of the... |
Switch.
There's a 2/3 chance that you'll choose a goat, and a 1/3 chance you'll choose the car.
If you chose a goat, after switching you will win a car. (Guaranteed)
If you chose a car, after switching you will win a goat. (Guaranteed)
Therefore, the chance you'll win a car is 2/3 if you switch.
Simply p... |
How many squares can you find in the pattern? |
i made a program for it, and it's algorithm is to get the number from user, reverse it and do the multiplication, if the reverse and multiplication is equall then print it for you.
here is a C# code:
Console.WriteLine("number from");
int a = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(... |
If you have a `Cube say 3 x 3 x 3`, you know that mathematically its made of `27(3*3*3) smaller cubes`. Now, just `remove the one full line of smaller cubes` (in this case `3 smaller cubes`).
Can you prove the remaining number of smaller cubes is always multiple of 6 ? |
If you have a cube, say, $3 \times 3 \times 3$, you know that mathematically it's made of $27$ ($3*3*3$) smaller cubes. Now, just remove one full line of smaller cubes (in this case, 3 smaller cubes).
Can you prove that the remaining number of smaller cubes is always a multiple of 6? |
Can anyone tell me what is the purpose of the outter dial of this watch? Notice how the scale is not linear and goes to 100. It can only be rotated counter-clockwise only.
This is the only picture I have.
Sorry, it's not really a puzzle but I didn't know which stac... |
What is the purpose of a weird non-linear watch dial that goes up to 100? |
That outer dial resembles the [slide-rule](https://en.wikipedia.org/wiki/Slide_rule#Circular_slide_rules) dial found on some watches, for example on various [Citizen Nighthawk](https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1067&bih=597&q=citizen+nighthawk+watch&oq=citizen+nighthawk+watch&gs_l=im... |
Switch.
There's a 2/3 chance that you'll choose a goat, and a 1/3 chance you'll choose the car.
If you chose a goat, after switching you will win a car. (Guaranteed)
If you chose a car, after switching you will win a goat. (Guaranteed)
Therefore, the chance you'll win a car is 2/3 if you switch.
Simply p... |
There are 10 Box, each containing 1000 sugar cubes. All sugar cubes in 9 boxes are 10 grams and the other one is containing 9 gram cubes.
There is a digital scale that you can use it ONCE.
Is there any way to find the box of 9 gram cubes? How?
Source: [Fekraneh.ir][1]
[1]: http://www.fekraneh.ir/tab-177/ind... |
There is 8 marbles that one of them is lighter than the others, and all other seven marbles have the same weight.
There is a balance scale that you can use it twice or once.
Is there any way to find the lightest marble? How?
source: [Fekraneh.ir][1]
[1]: http://www.fekraneh.ir/tab-177/index.aspx |
Which one is the lightest marble? |
It is a famous riddle that I have not seen it in Puzzling beta.
You are a prisoner somewhere with 2 doors and 2 guards. one of the doors will guide you to freedom and the other will cause you to hang and you don't know which one it is.
One of the guards always tell the truth and the other always lies. you don't k... |
Choose a guard and ask him, "If I asked you 'are you standing in front of the freedom door?', would your reply be 'yes'?"
- If you choose the truthful guard, he will give you an honest answer. Enter his door if he says "yes" and enter the other door otherwise.
- If you choose the liar, he will lie about what his ... |
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 tell the truth and the other always lies. You don't know which one is the truth-teller or the liar either.
You have to choo... |
The answer I've consistently heard to this is:
> If I asked what door lead to freedom, what door would the other guard point to?
If you asked the truth-guard, the truth-guard would tell you that the liar-guard would point to the door that leads to death.
If you asked the liar-guard, the liar-guard would tell y... |
You have to stay 7 days in a hotel outside your city. But you have forgot to bring your credit card and you are out of cash.
You have a silver necklace with 7 links. There is a rule in this hotel that residents should pay their rent every morning. The manager of hotel is well aware of your situation and offer you to... |
You have 12 liters of apple juice in a 12 liters bucket and you want to share it with your best friend. But you have an empty 8 liters and an empty 5 liters bottle.
How do you split the apple juice in half?
source: [fekraneh.ir][1]
[1]: http://www.fekraneh.ir/tab-178/index.aspx |
There is a running match, but there isn't anyone to judge; we have only information that the audience gave us (but we know their info is true). We the have name, rank, T-shirt color, and T-shirt number of each runner, as follows:
1. **Mahsa** won and she wore a red T-Shirt.
2. The girl who wore T-Shirt number 1 f... |
Who? What Color? Rank? Number? in a running match |
How many squares can you find in the picture? |
What word has that many letters? Please answer by yes or no.
- Yes -> 3
- No -> 2
- Er... I can't. -> 1 |
Find the next number in the series? |
There are 8 marbles that one of them is lighter than the others, and all other seven marbles have the same weight.
There is a balance scale that you can use it twice or once.
Is there any way to find the lightest marble? How?
source: [Fekraneh.ir][1]
[1]: http://www.fekraneh.ir/tab-177/index.aspx |
As everyone know in Sudoku sum of each row and column is 45. so all Sudoku solutions are some kind of magic square. but my question is:
Have anyone seen a Sudoku puzzle combined with the magic square rule for all nine 3x3 squares? (even without diagonal sum)
Is it even possible to have such a puzzle? |
is there any sudoku puzzle combined with magic square? |
How to control whole board with 8 standard pieces (one king, one queen, two rooks, two knights, two bishops)?
P.S. If a piece stays on a cell it doesn't control it, so another piece must control it. |
How to control whole board with 8 standard pieces? |
As everyone know in Sudoku sum of each row and column is 45. so all Sudoku solutions are some kind of magic square. but my question is:
Have anyone seen a Sudoku puzzle combined with the magic square rule for all nine 3x3 squares? (even without diagonal sum)
Is it even possible to have such a puzzle?
edit: Th... |
How to control the whole board with 8 standard pieces (one king, one queen, two rooks, two knights, two bishops)?
P.S. A piece doesn't control a cell simply by staying on it, so another piece must control it. |
How to control the whole board with 8 standard pieces? |
James has a defective clock in his room. The clock is digital, and some of the seven bars on its units digit are broken. A bar that works is on when it should be and off when it should be, whereas a broken bar is off regardless of the time.
1. James enters his room and glances at his clock. He knows how many bars a... |
>You said - **"The clock is digital, and some of the seven bars on its units digit are broken."**
and then at the end you say - **"In each of these four scenarios, what is the maximum number of broken bars, and which might it/they be?"**
Firstly this should mean that the answers to all the four questions should be ... |
The anti-intellectuals have won the war, and under the iron rule of emperor Nonotin anyone deemed too smart for their own good are gathered in prisons and labour camps.
But most of the science folks turn out to have never done a fair days work in their life, so they are worth little in the labour camps. In order to ... |
The anti-intellectuals have won the war, and under the iron rule of emperor Nonotin anyone deemed too smart for their own good are gathered in prisons and labour camps.
But most of the science folks turn out to have never done a fair days work in their life, so they are worth little in the labour camps. In order to ... |
James has a defective clock in his room. The clock is digital, and some of the seven bars on its units digit are broken. A bar that works is on when it should be and off when it should be, whereas a broken bar is off regardless of the time.
Assume that in each scenario, unless otherwise stated, James knows there are... |
Let $N$ be some number. Let $R$ and $S$ be [semiprimes](http://en.wikipedia.org/wiki/Semiprime) [ie, each is a product of two prime numbers] such that $R \le N \le S$.
For quite a few numbers $N$ we can find $R, S$ such that $S-R$ is small; eg, for $N=50$, we have $7\cdot7 = 49 < 50 < 51 = 3\cdot17$, giving $S-R=2... |
Let $N$ be some number. Let $R$ and $S$ be [semiprimes](http://en.wikipedia.org/wiki/Semiprime) [ie, each is a product of two prime numbers] such that $R \le N \le S$.
For quite a few numbers $N$ we can find $R, S$ such that $S-R$ is small; eg, for $N=50$, we have $7\cdot7 = 49 < 50 < 51 = 3\cdot17$, giving $S-R=2... |
James has a defective clock in his room. The clock is digital, and some of the seven bars on its units digit are broken. A bar that works is on when it should be and off when it should be, whereas a broken bar is off regardless of the time.
Assume that in each scenario, unless otherwise stated, James knows there are... |
The anti-intellectuals have won the war, and under the iron rule of emperor Nonotin anyone who deemed too smart for his own good has been brought in prisons and labour camps.
But most of the science folks turn out to have never done a fair day's work in their life, so they are worth little in the labour camps. In or... |
>You said - **"The clock is digital, and some of the seven bars on its units digit are broken."**
and then at the end you say - **"In each of these four scenarios, what is the maximum number of broken bars, and which might it/they be?"**
Firstly this should mean that the answers to all the four questions sh... |
The anti-intellectuals have won the war, and under the iron rule of emperor Nonotin anyone who has been deemed too smart for their own good has been brought to labour camps.
But most of the science folks turn out to have never done a fair day's work in their life, so they are worth little in the labour camps. In ord... |
The anti-intellectuals have won the war, and under the iron rule of emperor Nonotin anyone who has been deemed too smart for their own good has been brought to labour camps.
But most of the science folks turn out to have never done a fair day's work in their life, so they are worth little in the labour camps. In ord... |
Consider any large rectangle from which a smaller rectangular portion has been removed. The removed rectangular portion may have any orientation i.e. the remaining figure is not necessarily symmetric anymore.
Using a single cut how would you divide the given figure into two figures of equal area ? |
>You said - **"The clock is digital, and some of the seven bars on its units digit are broken."**
and then at the end you say - **"In each of these four scenarios, what is the maximum number of broken bars, and which might it/they be?"**
Firstly this should mean that the answers to all the four questions sh... |
I found this programming related problem too difficult for me. The problem asks to find 16 integers, positive, zero and negative ones are allowed and form a 4x4 grid
n1 n2 n3 n4
n5 n6 n7 n8
n9 n10 n11 n12
n13 n14 n15 n16
That square has 30 subsquares. Can one find a set of those 16 integers suc... |
I found this programming related problem too difficult for me. The problem asks to find 16 integers and form a 4x4 grid
n1 n2 n3 n4
n5 n6 n7 n8
n9 n10 n11 n12
n13 n14 n15 n16
That square has 30 subsquares. Can one find a set of those 16 integers such that sums of elements in subsquares contains... |
I have beein playing around with the question and came up with the following:
> At a party, you see a boy misbehaving and you try to locate the parents. You see Mrs Smith.
> - Hello, Mrs Smith, do you have children?
> - Yes. I have two.
> - Do you have a boy?
> - Yes, I do.
> You point at the boy. ... |
Is there any crime the three wise monkeys could collectively "witness" and not be able to indict the suspect? |
There are five fruits (Apple, Banana, Pineapple, Orange and Watermelon) that should be order in their places. But we have not enough container for them, there are only two bowls and two baskets. So one of the fruits will remain with no container.
We also know that both baskets are larger than the bowls.
1. Wate... |
Question: You have 3 baskets, one with apples, one with oranges and one with both apples and oranges mixed. Each basket is closed and is labeled with ‘Apples’, ‘Oranges’ and ‘Apples and Oranges’. However, each of these labels is always placed incorrectly. How would you pick only one fruit from a basket to place the lab... |
I found this programming related problem too difficult for me. The problem asks to find 16 integers and form a 4x4 grid
n1 n2 n3 n4
n5 n6 n7 n8
n9 n10 n11 n12
n13 n14 n15 n16
That square has 30 subsquares. Can one find a set of those 16 integers such that sums of elements in ... |
Well, as you have said, there is a risk to pick always the same fruit from the "apples and oranges" basket. So there is no certain answer, except if you pick all fruits from one basket.
If you pick one fruit from each basket, you must have one of one fruit and 2 of the other. Let's say you pick 1 apple and 2 orang... |
Well, as you have said, there is a risk to pick always the same fruit from the "apples and oranges" basket. So there is no certain answer, except if you pick all fruits from one basket.
If you pick one fruit from each basket, you must have one of one fruit and 2 of the other. Let's say you pick 1 apple and 2 orang... |
It is a little known fact that Santa Claus is in fact a vampire. Why else would he spend so much time near the North Pole and travel only at night? Yes, he fears daylight.
His problem is that during the summer, there is plenty of daylight on the North Pole. This is why, every equinox, he migrates to the other pole... |
Is there any crime the three wise monkeys (who see no evil, hear no evil, and speak no evil) could collectively "witness" and not be able to indict the suspect? |
Clearly it depends on your definition of "evil" - the third monkey, whose sight and hearing are not restricted in any way, is a perfectly good witness who could identify the culprit easily enough. Were you to declare that saying "It was John who robbed the bank / shot that guy / lit the fuse" was somehow *speaking evil... |
It depends on how much freedom the monkey who can "speak no evil" has. Does this mean that he can write? Sign language? If so, then he effectively has no limitations since he can communicate fully. Thus, there is no crime (apart from the monkeys being killed like in a previous answer) that he cannot indict.
If... |
The task is to decode the following: 5, 18, 92, 6, 1
Clues:
1. It's your name [my name is Jake]
2. Gliding o'er all, through all, Through Nature, Time, and Space, As a ship on the waters advancing, The voyage of the soul—not life alone, Death, many deaths I'll sing.
3. Your first guess (ascii) was definitely t... |
I created a visual puzzle, which my wife then implemented as part of a stained-glass window. I've no idea if it is (a) obvious, (b) stupid or hopefully (c) extremely clever, and hence would love to hear your opinion.
Here's a photo. What does it represent?
![Order and Chaos][1]
[1]: https://i.stack.imgur.c... |
There's an obvious generalization of [this problem][1]: There are a rather large number of prisoners, each of them seeing the color of the hat of all the following sad fellows bot not their; the hats may be of one of $n$ different colors, and everyone in turn must state the color of his hat, without uttering anything e... |
From as far back as psychologists [Robert Sternberg][1], and [Janet Davidson][2] argued that solving puzzles entails the ability to compare hidden information in a puzzle with information already in memory, and, more importantly, the ability to combine the information to form novel information and ideas<sup>1</sup>. Th... |
What drives the brain when creating puzzles? |
Can you draw something on a piece of paper that looks like a square and a circle at the same time? |
Are there at least N + 27 days in a random February?
if (N = 1) then (N + 27 = 28) --> Yes
if (N = 2) then (N + 27 = 29) --> Maybe
if (N = 3) then (N + 27 = 30) --> No
|
Are there at least $N + 27$ days in February, where $N$ is your number?
- if $(N = 1)$ then $(N + 27 = 28)$ --> Yes
- if $(N = 2)$ then $(N + 27 = 29)$ --> Maybe
- if $(N = 3)$ then $(N + 27 = 30)$ --> No
|
Grelling's Paradox ( I think) is about certain types of words. Call an adjective heterological if it does not desribe itself ; like 'long' , or German or monosyllabic. Call an adjective autological if it can describe itself; like 'short' , English or polysyllabic. So the paradox is , what is heterological , is it autol... |
I found a Very Difficult IQ Test on web. You are the guys who are looking for things like this, so it may look familiar for you.
one of it's questions is:
> What is the box suggesting?
>![enter image description here][1]
>1. 123456789
>2. 176h54308
>3. 627456934
>4. 126485704
>5. 673258719
I have seen... |
I found a Very Difficult IQ Test on web. You are the guys who are looking for things like this, so it may look familiar for you.
one of it's questions is:
> What is the box suggesting?
>![enter image description here][1]
>1. 123456789
>2. 176h54308
>3. 627456934
>4. 126485704
>5. 673258719
I have seen... |
I found a [Very Difficult IQ Test][2] on web.
One of it's questions is:
> What is the box suggesting?
>![enter image description here][1]
>1. 123456789
>2. 176h54308
>3. 627456934
>4. 126485704
>5. 673258719
I have seen the answer and it is the first option (123456789), but there was no clues for th... |
I just came up with the following puzzle. I don't think anything like this has been asked here before, but I may be wrong.
What's the next symbol in this sequence?
![(ヨ, ミ, ワ, something, something, something][1]
[1]: https://i.stack.imgur.com/1DH6C.png |
There is no paradox as long as you realize that, when you say "all adjectives can be categorized as autological *or* heterological", the "or" is not exclusive.
To explain this a little bit better, let's try to describe this using math syntax. Let's call $f$ a function that returns the relevant description of a word.... |
It is a little known fact that Santa Claus is in fact a vampire. Why else would he spend so much time near the North Pole and travel only at night? Yes, he fears daylight!
His problem is that during the summer, there is plenty of daylight on the North Pole. This is why, every equinox, he migrates to the other pole... |
[Grelling's Paradox][1] is about certain types of words. An adjective is *heterological* if it does not desribe itself; like 'long', 'German', or 'monosyllabic'. An adjective is *autological* if it does describe itself; like 'short', 'English', or 'polysyllabic'. So the paradox is,
>What is *heterological*, is it ... |
I came across this puzzle somewhere on the interwebs. Has stumped me for an answer for quite sometime. Helpplease?
> Someone picks, at their will, two cards from a deck of cards. The
> cards have different numbers, i.e one card is higher than the other. (In
> other words, the person picks two distinct numbers in t... |
Lately I 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 more.
Here it is:
Peter got 10 from his father, 10 from his mother and went to buy some grocery. He spent only 17.
Once he is back home he gives back 1 to his father, ... |
Any solution to this puzzle? |
#Intuitive Solution:
When you first look at the problem, intuitively, it makes sense to first split the 25 horses into 5 groups and then run a race with each group - we will call these the 5 heats.
In the 6th race, you can run just the winners. Lets say that the results of this race are as follows:
1st ... |
You can see the rules for [pointing problem at this article][1]. It has been clarified that there is no solution to this question.
But, what if we remove the diagonal rule? is there any solution?
[1]: http://puzzling.stackexchange.com/questions/2303/write-1-to-9-digits-in-the-table-each-pointing-to-next-3x3-gri... |
Here is a twisted solution.
> Go to any guard, point at a door and ask:
> Among the propositions 1. "You are a liar", 2. "You will reply negatively" and 3. "This door leads to freedom", is there an odd number of true propositions?
If you get the answer yes:
If the guard is a truthteller, the number of truth... |
I am wondering when [the missing dollar puzzle][1] first appeared. I am sure I read it forty years ago or so, but maybe it is much older. Does anyone knows it?
[1]: http://puzzling.stackexchange.com/q/2297/70 |
How to let all people in Group A talk to all people in Group B in a shortest amount of time? |
What is a geographical similarity between Cambridge University and Oxford University related to their 'titles'? |
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