Post your puzzles here on the Puzzle Post:
And I see no reason why multiple puzzles/lateral thinking riddles/etc. cannot exist side by side at the same time as long as the potential solvers of said puzzles make it clear which one they were replying to.
Here is a starter-off and probably the best puzzle I have ever encountered in my life.
I'm not sure how famous this puzzle is so if you already know the answer please do the respectful thing and leave it to those who have not already had the enjoyment of figuring it out to...figure it out...
Four people are in a room, labelled A,B,C,and D...
Each wear either a black or a white hat, as shown in the illustration below:
[imgzoom]http://i28.photobucket.com/albums/c201/Mandle/BestPuzzle01_zps5jbqjiv6.png[/imgzoom]
Each person faces to the left.
Each person cannot see the colour of the hat they are wearing.
Each person knows their A,B,C,D order, meaning that they know how many people are in front of them and how many are behind them.
All of the people know that there are 4 people in the room.
All of the people know that there are 2 white hats and 2 black hats.
They are not allowed to turn around or speak to each other.
The black bar labelled W represents a wall dividing the room which cannot be seen through, nor is it a mirror (no cheap tricks like that).
A can only see the wall right in front of them.
B can only see the wall right in front of them.
C can see the colour of B's hat.
D can see the colour of B's hat and C's hat.
The object of this puzzle is to determine which person will first correctly and with 100% certainty be able to say if they are wearing a black hat or a white hat, and also be able to explain how they knew.
SO:
Which person knew the colour of the hat they were wearing and how did they know?
(Please hide answers so that others may have a fair go at the puzzle with no spoilers)
Spoiler
Is it person C, because he knows that if he was wearing a white hat, the person behind him would be able to tell the colour of his own hat right away?
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Yeah I'm with Cuiki.
I will give a deeper explanation.
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Don't look if you haven't already had a good go at working it out.
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Seriously, have another go.
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If C were wearing a white hat then D would have seen two white hats in front of him and announced he's wearing black. But D won't have said anything, so C can work out that D must be seeing one black hat and one white hat. And since he know's that B's hat is white, his own must surely be black.
Nice puzzle. We've had similar threads before and some variations of these hat puzzles came up but I don't think this particular version with the wall came up, so nice one.
Well, I think I'll let someone else come up with the next one.
Unless you'd like to be bored to death with my probability puzzles... :P
Cuiki & Stupot are both correct of course. Well done! As with all great puzzles as soon as you find the correct answer you already know it to be correct without having to be told so.
But I urge you to try this puzzle out yourself and give it a decent try before looking at their answers. There is a real sense of satisfaction from solving it.
Quote from: Cuiki on Sat 12/09/2015 22:09:31
Well, I think I'll let someone else come up with the next one.
Unless you'd like to be bored to death with my probability puzzles... :P
I think for this thread it's best if anyone can just post up a puzzle at any time, even if there are multiple puzzles running at the same time. Puzzles that are not ridiculously well-known already are quite hard to come by so I think the winner-posts-next-puzzle format will not work very well.
I have one of my own devising. It's probably not all that great but at least it's ungoogleable:
A man gets out of the way of a fast-moving car just bare seconds before it would have hit and most likely killed him, and yet he is not in the slightest bit shaken-up by the experience. The man was aware of the vehicle (he's not blind etc.), he's not drunk or on drugs, and he is not a professional stuntman or anything like that.
What's the reason for his cool demeanor?The answer is not based on word-play or puns within the question etc. What you see is what you get. Hide answers please.
Spoiler
Er.... he's crossing a busy street? Daily pedestrian fatalities in major urban centres suggest he would be nonplussed by the velocity of the traffic heading towards him: otherwise, how can you account for their unnecessary risk taking? (roll)
Quote from: Baron on Sun 13/09/2015 05:00:21
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Er.... he's crossing a busy street? Daily pedestrian fatalities in major urban centres suggest he would be nonplussed by the velocity of the traffic heading towards him: otherwise, how can you account for their unnecessary risk taking? (roll)
100% correct...yeah...like I said...it's probably not that great a puzzle...
SPOILER ALERT:
Spoiler
We all feel cars pass by just behind us when crossing a main road and hardly think twice about how close we just came to death...
So the moral of this puzzle is: STAY SAFE GUYS!!! And never assume that the person driving the car is not typing on their pho...
OH SHIIIIIT!!!!....
(Phew...that was a close call...)
(http://i28.photobucket.com/albums/c201/Mandle/BusPuzzle01_zpsjycwsptk.png)
Which way is the bus moving?
A or B?
And why?
(hide answers)
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Depends on which country you are. ;)
A in any country that drives on the right side, B in all other countries that drive on "the wrong side". :P (laugh)
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Why? Cause all you can see are windows, so door is on the other side.
Quote from: Cassiebsg on Sun 13/09/2015 08:51:39
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Depends on which country you are. ;)
A in any country that drives on the right side, B in all other countries that drive on "the wrong side". :P (laugh)
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Why? Cause all you can see are windows, so door is on the other side.
Yup...It actually doesn't matter if you choose A or B as long as you are able to explain why...
And you nailed it!
Alec and Alexia grow carrots.
Carlo and Clover grow oranges.
Paula and Phillip grow apples.
Michael and Michelle grow what?
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Lemons
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Last letter of their first and surnames = First two letters of each fruit/vegetable
Quote from: Gurok on Sun 13/09/2015 09:39:30
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Lemons
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Last letter of their first and surnames = First two letters of each fruit/vegetable
Correct!
Give me some time...I'm gonna think up a puzzle that has never been done before...
I might need some time...Like Deep Thought needed some time...
In the meanwhile please post your own puzzles...
Here is one interesting numbers puzzle I was told about by my math teacher.
1
11
21
1211
111221
312211
13112221
1113213211
31131211131221
What is the next number?
This may be considered a hint, so I hide it under spoiler:
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According to his story, this puzzle was introduced at some mathematician symposium and caused quite a ruckus when it was found that big mathematicians could not solve it :).
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13211311123113112211
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In the first line is one "1" - that means line 2 is "11"; in line 2 are two "1" - so line 3 is 21; in line 3 is one "2" and one "1" - 1211 - and so on.
Sinitrena is correct.
How about an easy one?
A book has 973 pages, numbered consecutively from 1 to 973. On every page is just a single sentence. On page 1: "There is exactly one false statement in this book." On page 2: "There are exactly two false statements in this book." And so on: On every page there is a single sentence stating that there are exactly as many false statements in the book as the page you are on.
Is there a page that tells the truth and if yes, which one?
Quote from: Sinitrena on Thu 17/09/2015 15:56:26
A book has 973 pages, numbered consecutively from 1 to 973. On every page is just a single sentence. On page 1: "There is exactly one false statement in this book." On page 2: "There are exactly two false statements in this book." And so on: On every page there is a single sentence stating that there are exactly as many false statements in the book as the page you are on.
Is there a page that tells the truth and if yes, which one?
Well, I guess
Spoiler
It is page 972 that tells that there are 972 false statements in this book.
Correct. (nod)
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CW is correct. The logic behind it:
There can be at most one statement correct: if there were two or more they would always contradict each other.
Assume there was no correct statement then there would be 973 false statements. This is exactly what the statement on page 973 says. But this statement would be true then so this contradicts.
Assume there is one, then the other statements would be false so 973 - 1 = 972 statements would be false. This is exactly what the statement on page 972 says.
This is the correct answer.
Edit: too late :P
Quote from: Sinitrena on Thu 17/09/2015 16:33:55
Correct. (nod)
Very nice puzzle!
A quickie:
What did Pinoccio say about his nose to cause a paradox?
My nose is growing?!
My nose will be growing soon.
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My nose will never grow.
Let's look at the answers one by one:
@ selmiak: "My nose is growing."
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His nose was not growing at the time he said it was growing therefore what he said is a lie. Therefore his nose starts growing but this does not create a paradox as the moment he said it was growing has already passed...
"My nose will be growing soon."
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The word "soon" is a non-specific time-frame. It could mean 5 minutes from now or 2 weeks from now. He could easily tell a lie during that time so there is no paradox.
"My nose will never grow."
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This is a lie so his nose will grow. His nose grew so the original statement is still a lie. Hence: No paradox.
Okay, I can make it more specific:
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My nose will start growing after I say this.
Quote from: Crimson Wizard on Sat 19/09/2015 17:39:22
Okay, I can make it more specific:
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My nose will start growing after I say this.
Still no paradox because:
Spoiler
"after I say this" could still imply any length of time after he said it. It could be weeks afterwards in which case there is no paradox because he could have told any number of lies in the meanwhile...
Maybe I should add "just"?
Ahhhh...I see the new edit...
Replying...
Oh well, what about
Spoiler
My nose will start growing as a result of me saying this.
Hahahaha, you are totally outpacing my edits...just a sec please while I compute in my brainbox...
Quote from: Crimson Wizard on Sat 19/09/2015 17:54:15
Oh well, what about
Spoiler
My nose will start growing as a result of me saying this.
And I'm honestly not trolling (And I'm just realizing myself how exact the phrasing must be to create the paradox. This is a much better puzzle than I first expected and challenges both the host and the player equally):
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He says: "My nose will start growing as a result of me saying this."
But the problem is that the word "result" could still refer to a vague and possibly unconnected event in the future.
What about :
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My nose will be longer in 3 seconds.
Quote from: Creamy on Sat 19/09/2015 18:41:09
What about :
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My nose will be longer in 3 seconds.
I can say:
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"I exist."
In less than three seconds...So I think Pinocchio can too...
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"I can make my nose grow by telling the truth."
EDIT: or "I can make my nose grow at will, and here's the proof!"
I dunno. It's pretty convoluted. :-D
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This statement will make my nose grow.
Spoiler
QuoteMy nose will be longer in 3 seconds.
QuoteI can say "I exist." in less than three seconds...So I think Pinocchio can too...
It could be 5 or 10 seconds, it doesn't matter :
- if nothing has happened when the time is over, Pinocchio has lied so his nose should have grown longer just after he spoke > paradox.
- If his nose is longer when the time is over, Pinocchio has said the truth, so his nose shouldn't have grown longer in the first place > paradox
according to this statement my nose will grow or will not grow!
Quote from: Mandle on Fri 18/09/2015 00:34:42
What did Pinoccio say about his nose to cause a paradox?
Spoiler
"I went back in time and fathered my own nose." (nod)
The nose is a lie!
Sorry...been a bit busy proofreading and editing the english demo of "Chronicle Of Innsmouth" (which is almost ready for launch) and nursing my wife who threw out her back at work, amongst other stuff...
The answer was:
Spoiler
"My nose will grow now."
So I think Cuiki got the closest...
Anyways: NEEEEXT!!!
Sorry, I didn't mean to rush you or anything.
QuoteSo I think Cuiki got the closest...
Naah, I really didn't. :tongue: I think we were pretty much all there - just variations of one and the same idea.
Besides, if Pinocchio's nose is allowed to take a few moments to buffer before it does anything, "now" probably isn't the right word either...
Quote from: Cuiki on Mon 21/09/2015 14:33:29
Sorry, I didn't mean to rush you or anything.
QuoteSo I think Cuiki got the closest...
Naah, I really didn't. :tongue: I think we were pretty much all there - just variations of one and the same idea.
Besides, if Pinocchio's nose is allowed to take a few moments to buffer before it does anything, "now" probably isn't the right word either...
Well...If you said "My nose will grow 3 seconds from now" then potentially Pinocchio would have time to tell a lie in the meanwhile in which case the original statement would have been true and no paradox.
Spoiler
The word "now" means instantly which means that it would have to be a result of what was just said. This creates the paradox in that if his nose grows then it was true in which case it wouldn't but if it didn't then what he said was a lie in which case it would grow...etc etc...
Well, what I meant was: if he says "My nose will grow now," and his nose takes a few miliseconds to process that information, he may as well be telling a lie when his nose starts growing - as "a few miliseconds" into the future wouldn't have to be understood as "now", technically speaking - and so he wouldn't be causing a paradox.
QuoteWell...If you said "My nose will grow 3 seconds from now" then potentially Pinocchio would have time to tell a lie in the meanwhile in which case the original statement would have been true and no paradox.
That's assuming he does, but what if he doesn't? :P
Quote from: Mandle on Mon 21/09/2015 13:55:14
Spoiler
"My nose will grow now."
So I think Cuiki got the closest...
OH COME ON!!!!
Quote from: Mandle on Sat 19/09/2015 17:25:57
@ selmiak: "My nose is growing."
Spoiler
His nose was not growing at the time he said it was growing therefore what he said is a lie. Therefore his nose starts growing but this does not create a paradox as the moment he said it was growing has already passed...
is growing, present, like, now!!!
I demand a recount! You were just disappointed by and didn't expect my superior intellect and that I instantly solved this no-puzzle and therefore dragged this easy riddle over 2 pages just to confuse forummembers by saying no, no, no, no again. You just kept hiding behind this no and made everyone reply and made everyone screw their brains and made everyone do some more postings in this thread. Pffft, I will never ever reply to your posts again! At least not until the next time I reply to one of your posts! :P
Actually I agree with Mandle.
"is growing" is not a paradox, cause if it is growing when he said it then it's the truth, if it's not growing when he says it then it's a lie and thus his nose will grow. :P
I still don't get it :-D
I too would like to debate the immediacy of the word "now", which can refer to different periods depending on the scale of time conceptualized by the person uttering the word. For example, Homer J. Simpson once marvelled that "they have the internet on computers now," clearly not referring to that exact instant but to a vaguely current-ish time period. Likewise, Shakespeare's Richard III says in the opening lines "Now is the winter of my discontent / Made glorious summer by this son of York," referring again to a vaguely current state that began with their victory in battle before the play even began (that is, several hours or days before hand). I think "My nose will grow presently" or "My nose will grow right......NOW!" would be more suitable answers. :P
Quote from: Baron on Tue 22/09/2015 03:32:38
"My nose will grow right......NOW!"
Yes...I think that phrasing is the best.
I like Atelier's sentence the best actually. (nod)
I think it's time for a new puzzle!
When is half of 10 = 5, half of 9 = 4, half of 11 = 6 and half of 12 = 7?
Quote from: Sinitrena on Sat 26/09/2015 22:39:50
I think it's time for a new puzzle!
When is half of 10 = 5, half of 9 = 4, half of 11 = 6 and half of 12 = 7?
Spoiler
Is this something to do with Roman numerals?
X V
IX IV
XI VI
XII VII
I'm not sure exactly how this answers the question but there is a definite pattern there. Replacing X with V gives you the "half" figure in each one.
I guess
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half the X is a V (disregard the lower portion) and half the I would still be an I
Holy crap you guys are fast!
Way too fast, guys!!!
Seriously, 25 minutes for the correct answer? 8-0
Silly riddle I just thought of (and I'm probably not the first):
What kind of tune can no one hear? Why?
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You can never hear your own fortune because it always lies in the future and fortune tellers are bogus...
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Neptune because it's too far away!
@Mandle. Sorry I somehow missed your post. Good guess, but nope.
@CaptainD. YES! you got the right answer. But not quite the reasoning I had in mind:
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Neptune is in space, and as we know: "in space no one can hear [anything, like people screaming, for example]".
Quote from: Stupot+ on Tue 29/09/2015 23:44:23
@CaptainD. YES! you got the right answer. But not quite the reasoning I had in mind:
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Neptune is in space, and as we know: "in space no one can hear [anything, like people screaming, for example]".
Heh... your reasoning is much better than mine! :-D
A Romantic Tale
Just before sleeping,
I sought out my love:
Two miles for a dove,
I hope noone was peeking...
Upon waking up,
I sought her of course:
Ten miles for a horse,
Why's the distance gone up?
I'm guessing this might be referring to
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your shadow? It is will be different lengths at different points in the day due to the position of the sun.
I'm not sure at all about this one...
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Seems like it must be SOMETHING to do with the position of the sun, not sure how the distances relate, or possibly refer to clock positions?
First try:
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You are in a litter and someone was carrying you 8 miles while you were asleep.
Second try:
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It's something like a fjord with your love being on the other side. The bird can fly over it, so it's only two miles. The horse has to go around, so it's ten miles.
Quote from: cat on Wed 07/10/2015 15:11:57
Second try:
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It's something like a fjord with your love being on the other side. The bird can fly over it, so it's only two miles. The horse has to go around, so it's ten miles.
This is mostly correct. But why do YOU have to:
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Go around after waking up when you could go over before you slept?
Quote from: cat on Thu 08/10/2015 07:52:00
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Tides?
Hmmmmm...
Not the answer I had in mind but it does make sense so it must be counted as correct.
Well done!
There is another possible answer though...
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A bridge that retracts at certain hours of the day?
Quote from: CaptainD on Thu 08/10/2015 09:50:17
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A bridge that retracts at certain hours of the day?
Hmmmm...seems a bit unlikely...Unless living in Myst...But okay: possible
Another possibility maybe:
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You can go over it when it's frozen but have to walk round it when it's water
Quote from: CaptainD on Thu 08/10/2015 12:03:06
Another possibility maybe:
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You can go over it when it's frozen but have to walk round it when it's water
YES! This is 100% correct. Now the only part of the puzzle to answer is:
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How did the entire lake unfreeze while the main character was sleeping?
Quote from: Cassiebsg on Thu 08/10/2015 16:21:29
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He's a bear! :P
Well done Cassie! The full answer was:
Spoiler
The main character is a bear and so during the start of winter he visits his mate by waking across the frozen lake between their territories. Then he hibernates for the winter. After waking up in spring he must walk all the way around the now unfrozen lake to visit her again.
For a puzzle I made up on the fly I think it's alright. It has a few flaws in that there are many imaginable alternate solutions (and the fact that I rhymed a word with itself). If presented kinda like it ended up here: as a Q&A session with the teller and with the rule that only the exact right answer will suffice I think it could be a fun one at a puzzle-solving game during a kid's birthday party for example.
NEXT!!!
Nice puzzle Mandle ;-D