Post a riddle, entertain me!

I like riddles, puzzles and brain twisters. Do you?

If yes, I’ll get this thread rolling:

First, a classic:

What is greater than God,
And more evil than the Devil?
The rich need it,
And the poor have it.
If you eat it, you die.

answer wrote:

[color=white]Nothing[/color]

Next, the light bulb problem.

You are in a closed facility that consists of three, windowless rooms. The first room has three light switches, labeled A, B and C. The second room is a small corridor, which serves as a pressurization chamber between the first and third rooms. The third room is empty save for three incandescent light bulbs hanging from a low ceiling. These bulbs are labeled 1, 2 and 3 and are connected to the switches in the first room, but which switch connects which bulb is unknown. The bulbs in the third room are not turned on (The switches start in the off position). There is no way to see room 1 from room 3 and no way to see room 3 from room 1.

You start out in the first room and may flip the three switches in any manner you see fit, and may stay in this room as long as you feel necessary. Once you enter the pressure chamber, you cannot return to the first room; you may only proceed to the third room.
Given these rules, how can you determine which switch connects to which light bulb?

answer wrote:

[color=white]First, flip switches A and B to the on position and wait ten minutes. Turn off switch B and quickly proceed to the third room. Whichever light is still on connects to switch A, as that is the switch you left on. Now feel each of the remaining light bulbs. The warm light bulb connects to switch B, which you had left on for ten minutes. The cold light bulb connects to switch C, since you never turned it on. [/color]

Next, a Little Late.

A man is sitting at a desk, with a light bulb hanging from the ceiling. Suddenly, a man bursts into the room waving an envelope and the light bulb flickers. The man sitting at the desk sighs and says, “You’re too late.” The man who had just entered the room sulks, and throws the envelope into the trash can. He leaves the room. What was in the envelope?

answer wrote:

[color=white]A pardon from the governor being delivered to a prison warden. The flickering lights indicate that an execution by electric chair had just taken place. Too bad for the prisoner![/color]

Now, the Prince’s Crown

A king is about to die and he must bestow his kingdom upon one of his three sons. He gathers his sons in a chamber and says, “My sons, my time to die is almost here and I must pass my crown to one of you. You have all proved yourself to be fine leaders, but I have one final test which you must pass to assume my throne. This is a test of wisdom. To rule this land, you must know your crown.”

The king then has his sons blindfolded and has a crown placed on each of their heads. Each crown has a jewel placed in it that is visible to those who gaze upon it, but above the view of the person wearing it.

The king then says to his sons, “Each of you now wears a crown with a jewel in it. The crown either has a blue sapphire or possibly a red ruby. One of you has a blue sapphire, but beyond that, the three crowns may have any combination.”

“Three sapphire crowns, and no ruby crowns.”
“Two sapphire crowns and one ruby crown.”
“or a sapphire crown and two ruby crowns.”

“Obviously, you cannot see your own jewel, so you must rely on wisdom to determine which jewel you possess. If you guess incorrectly, then you are a shame to your country and will be executed. You have one hour. If you do not guess before then, you will be banished, and I will find a new heir.”

The king then orders his sons to remove the blindfolds and the princes stand stunned, having to complete an impossible task. How to guess the jewel on their own head, with only one clue? One of the crowns must contain a sapphire.

After a few minutes of silence and nervous glances at each others’ crowns, one of the princes looks into one of his brothers’ eyes and yells, “Mine is the blue sapphire!”

The king congratulates his son, and new King. How did the prince figure this test out?

Hint: He did not look into the reflection of his brothers’ eyes and there are no mirrors

answer wrote:

[color=white] Let’s take this step by step.

Obviously, the princes have no way of physically seeing their own jewel, but their reactions to the riddle would provide the necessary evidence to win the challenge.

Let’s take the easy case: A sapphire and two rubies. Two of the princes would see a ruby and a sapphire and therefore be confused and not speak. The third prince would see two rubies and immediately claim to have the sapphire, as the rules state that there are not three ruby crowns.

Now, the more difficult case: Two sapphires and one ruby. The prince wearing the ruby would see two sapphires, and therefore be uncertain if he wore the third sapphire or the only ruby. Now, the two other princes see a ruby and a sapphire, and at first are unsure whether or not they have a sapphire or a ruby. Impasse, right?

Almost. Let’s say A has the ruby, and B and C have sapphires.

B knows A has a ruby and C has a sapphire.
B also knows that if B has a ruby, C would immediately claim to have the sapphire. (because there can only be a maximum of two rubies)
Therefore, B knows that if C is quiet, then C is uncertain, because he also sees a sapphire and a ruby.
Which means B knows that B has a sapphire,
And he can claim as such.
In this case, both B and C are capable of winning.

In the last case, there are three sapphires and no rubies.

This case is a situation in which the proceeding two cases come together.

A, B and C all have sapphires.

A knows that B and C have sapphires.
A knows that B and C are silent, meaning each of them only sees blue sapphires.
A knows that the only case in which everyone is silent, is when everyone is unsure as to whether or not they have the ruby.
Since all of them are silent, none of them have rubies.
A, B or C can all win, by claiming to have sapphires.

The winner of the game is the one who can understand both the rules of the game as well as its players.
[/color]

The last one still confuses me a bit, but it might be a good way to stretch your brains a bit.

Edit: Ok, the crown one has been edited for clarification. There are three sons, and three crowns. Each crown has one stone. At least one crown has a sapphire, yielding three crown possibilities.

I'm looking forward to some Goodjer riddles!

I don't buy the last one.

[color=white]A could have a Ruby. Then B and C both see a Ruby and a Sapphire they would be confused as to whether they have a Sapphire or not. If A speaks up, he's dead.[/color]

A man was to be sentenced, and the judge told him, "You may make a statement. If it is true, I'll sentence you to four years in prison.

If it's false, I'll sentence you to six years in prison." The man made his statement and the judge let him go free. What did he say?

answer wrote:

[color=white]The man said "You'll sentence me to six years in prison."[/color]

Not sure about that last step, either.

[color=white]As far as I can tell, silence only means that they see an emerald. If A sees two emeralds, then A knows that the silence of B and C may be because they see each other's emerald.

From the perspective of the Ruby in the 2-sapphire scenario, there's no way to know. Only the two sapphire-wearers have a chance at winning.[/color]

In puzzles like the last one, you have to assume that everyone is perfectly logical, or else it does fall apart like you stated, kaos.

Here's a good one:

Assume there are about 6.5 billion people on Earth at this time. What is the estimated product of the number of fingers these people have?

[color=white]Zero. All it takes is one person with no hands to make the product zero.[/color]
kaostheory wrote:

I don't buy the last one.

[color=white]A could have a Ruby. Then B and C both see a Ruby and a Sapphire they would be confused as to whether they have a Sapphire or not. If A speaks up, he's dead.[/color]

I admit, there is a leap here, but

[color=white]It may be a matter of immediacy.

Scenario 1) If A sees two rubies, he speaks right away. (within seconds)
Scenario 2) If A sees a ruby and a sapphire, he waits for the person with the sapphire to make a move. If no move is made right away, then scenario 1 cannot happen and A would immediately claim the sapphire. (after a few seconds)
Scenario 3) If A sees two sapphires, he must wait for the other two people. This scenario would take the longest.

This riddle is not my own, but I thought it was interesting. The main problem with the riddle is the assumption that the princes are familiar enough with the setup of their task to judge the reactions of their brothers. Also, in any scenario, the person with the ruby can never be certain of having a ruby and cannot win using logic and is therefore doomed to lose. You would mostly have to focus on the fact that in the prompt, a person with a sapphire wins, and because he waits for a bit, one can assume everyone actually had sapphires anyway.[/color]

Does a bear sh*t in the woods?

For the gem one (which I've seen in a couple of different contexts before) it helps if time is discretized in some way. The one I recall had people who could only leave an island if they figured out what colour was on their head. The boat for carrying people away only came once per day. This gets rid of the problem Kaos and Wordsmythe had, since if no one leaves on the first boat, then everyone knows that there's more than one sapphire.

4dSwissCheese wrote:

For the gem one (which I've seen in a couple of different contexts before) it helps if time is discretized in some way. The one I recall had people who could only leave an island if they figured out what colour was on their head. The boat for carrying people away only came once per day. This gets rid of the problem Kaos and Wordsmythe had, since if no one leaves on the first boat, then everyone knows that there's more than one sapphire.

But it still doesn't help if the other two have a "winning" color. They leave and you're stuck there wondering if you've got the "winning" color or not. From your perspective, there is no difference between you being a winner or a loser.

Yep, again, that one wasn't my own, but it is inherently flawed.

Winning negates the possibility of set time frames.

The original can still make sense if you accept that the princes were both logical and knew each other well enough to estimate how long they would be willing to wait for a win condition.

So, not a great riddle, but it gives me an excuse to find a better one!

kaostheory wrote:
4dSwissCheese wrote:

For the gem one (which I've seen in a couple of different contexts before) it helps if time is discretized in some way. The one I recall had people who could only leave an island if they figured out what colour was on their head. The boat for carrying people away only came once per day. This gets rid of the problem Kaos and Wordsmythe had, since if no one leaves on the first boat, then everyone knows that there's more than one sapphire.

But it still doesn't help if the other two have a "winning" color. They leave and you're stuck there wondering if you've got the "winning" color or not. From your perspective, there is no difference between you being a winner or a loser.

In the gem one...

[color=white]All the crowns have 3 gems in them and each combination has at least 1 sapphire (3S+0R, 2S+1R or 1S+2R). To win, the prince only has to identify the type of any one of the three gems in the crown he wears, by saying if they have a sapphire or a ruby. Since all of them have at least 1 sapphire, they didn't actually need to have see in order to know enough to answer the question.
[/color]

The riddle may have been unclear.

Each crown has one gem, but there were three crowns.

So the combinations were sets of three crowns, not sets of three jewels. I'll change the OP to clarify.

Frackin' double post.

Here's another way to look at it (again, we have to assume all 3 princes are perfectly logical in their actions):

[color=white]There are 7 possible cases for the crown combinations, with R for ruby and S for sapphire:
  1. RRS
  2. RSR
  3. SRR
  4. RSS
  5. SRS
  6. SSR
  7. SSS

All 3 open their eyes, and being perfectly logical, if any of cases 1-3 were the case, there'd be an immediate call of "Sapphire" by the sapphire wearer, and they'd win. All 3 of them know this, so all 3 know that, as no immediate call has happened, cases 1-3 are incorrect.

Cases 4-6 are exactly the same as cases 1-3, except reversed for the ruby. All any of the princes would have to do is see 1 ruby, and they'd immediately know they had a sapphire on their head. So, while delayed, there'd be a fast response of "Sapphire!" by someone if cases 4-6 were the case. The only screwed prince would be the one with the ruby, as he would never have enough information to determine his gem. Since there still hasn't been a call, they'll knock cases 4-6 out.

Since, at this point, cases 1-6 have been discarded, it winds up that each of the perfectly logical princes just has to go through the mental gymnastics faster than his brothers in order to be the one to realize only one case exists, #7, and thus he has a sapphire on his crown.[/color]

Oh, and if anyone was interested, here's the island version of the crown puzzle:

From Gamespot forums:

A group of people with assorted eye colors live on an island. They are all perfect logicians -- if a conclusion can be logically deduced, they will do it instantly. No one knows the color of their eyes. Every night at midnight, a ferry stops at the island. If anyone has figured out the color of their own eyes, they [must] leave the island that midnight. Everyone can see everyone else at all times and keeps a count of the number of people they see with each eye color (excluding themselves), but they cannot otherwise communicate. Everyone on the island knows all the rules in this paragraph.

On this island there are 100 blue-eyed people, 100 brown-eyed people, and the Guru (she happens to have green eyes). So any given blue-eyed person can see 100 people with brown eyes and 99 people with blue eyes (and one with green), but that does not tell him his own eye color; as far as he knows the totals could be 101 brown and 99 blue. Or 100 brown, 99 blue, and he could have red eyes.

The Guru is allowed to speak once (let's say at noon), on one day in all their endless years on the island. Standing before the islanders, she says the following:

"I can see someone who has blue eyes."

Who leaves the island, and on what night?

There are no mirrors or reflecting surfaces, nothing dumb. It is not a trick question, and the answer is logical. It doesn't depend on tricky wording or anyone lying or guessing, and it doesn't involve people doing something silly like creating a sign language or doing genetics. The Guru is not making eye contact with anyone in particular; she's simply saying "I count at least one blue-eyed person on this island who isn't me."

I actually don't have the answer for this one...

Quintin_Stone wrote:

Does the pope sh*t in the woods?

Fixed.

Grubber788 wrote:

Oh, and if anyone was interested, here's the island version of the crown puzzle:

From Gamespot forums:

A group of people with assorted eye colors live on an island. They are all perfect logicians -- if a conclusion can be logically deduced, they will do it instantly. No one knows the color of their eyes. Every night at midnight, a ferry stops at the island. If anyone has figured out the color of their own eyes, they [must] leave the island that midnight. Everyone can see everyone else at all times and keeps a count of the number of people they see with each eye color (excluding themselves), but they cannot otherwise communicate. Everyone on the island knows all the rules in this paragraph.

On this island there are 100 blue-eyed people, 100 brown-eyed people, and the Guru (she happens to have green eyes). So any given blue-eyed person can see 100 people with brown eyes and 99 people with blue eyes (and one with green), but that does not tell him his own eye color; as far as he knows the totals could be 101 brown and 99 blue. Or 100 brown, 99 blue, and he could have red eyes.

The Guru is allowed to speak once (let's say at noon), on one day in all their endless years on the island. Standing before the islanders, she says the following:

"I can see someone who has blue eyes."

Who leaves the island, and on what night?

There are no mirrors or reflecting surfaces, nothing dumb. It is not a trick question, and the answer is logical. It doesn't depend on tricky wording or anyone lying or guessing, and it doesn't involve people doing something silly like creating a sign language or doing genetics. The Guru is not making eye contact with anyone in particular; she's simply saying "I count at least one blue-eyed person on this island who isn't me."

I actually don't have the answer for this one...

It has a straightforward answer, you just have to scale it down quite a bit to reach it.

spoiler wrote:

[color=white]100 days later, all 100 people with blue eyes leave.
Bah... my wording bugs me, so I'm editing it. Based on the riddle it'd be the 100th midnight after.[/color]

Grubber778,
You need to edit, you state both that the blind man steals and that his wallet is stolen.

Riddle #2

spoiler wrote:

[color=white]
On the 100th night all the blue eyed people leave.
Simplifying it to 1 Brown and 1 Blue:
on the first day the blue eyed person knows instantly they have blue eyes (since one of them must and the only other person does not)
2 brown and 2 blue:
first day each of the blue eyed folks sees 2 brown eyed people and 1 blue eyed person. If the other Blue eyes saw all three with brown eyes they'd leave that night. thus when they are there the next day, both blue eyes deduce that they have blue eyes
3 of each:
same as 2 of each, but an extra day is needed, because if there were only two blue eyes they'd both figure it out on day 2.
etc..
The most amusing part is that the number of brown eyed people is completely independant of the time frame it takes the blue eyed folks to figure it out. They literally do not factor into the calculation in any way other than they ae not blue eyed (i.e. not existing and not being blue eyed are trivial distinctions)[/color]

A man lives on the 20th floor of an apartment building. Each day, he rides the elevator all the way down to the lobby to go to work. When he returns from work in the evening, he rides the elevator to the 10th floor and walks the stairs the rest of the way, except on days that it rains. Assume that the elevator is perfectly functional. Why does he do this?

answer wrote:

[color=white]The man is of short stature and cannot reach the button for the 20th floor, except on days that he carries his umbrella.[/color]

Argh, I've created a monster of riddle, when it should have been easier. My wording of "combination," through people off. My apologies.

Here's a good one.

Three strangers are on an empty train car. One is blind, another is deaf and the last man is mute. The mute man sees the deaf man steal the blind man's wallet. How might the mute man let the blind man know that the deaf man has stolen his wallet?

answer wrote:

[color=white]Ignoring the obvious (and less fun) way of having the mute man spell out the theft on the blind man's hand, he could do the following:

The mute man could turn to the deaf man and mouth the words, "How dare you steal a blind man's wallet?"

The blind man will obviously not hear this, but the deaf man who can read lips, but not knowing that the mute is mute, will think that the mute man was making a loud accusation.

The deaf man will try to defend himself and say something along the lines of, "I did not steal his wallet!"

The blind man will hear this and be made aware of the crime. [/color]

Fixed.

For the island one -

[color=white]Being perfectly logical, they would realize that the rule preventing them from communicating is bullsh*t and they would go around telling each other what color their eyes are as to make the exodus more efficient.[/color]

I've got the ultimate riddle: women.

Rat Boy wrote:

I've got the ultimate riddle: women.

answer wrote:

[color=white] A hit of flunitrazepam or ruffie as it is commonly known.[/color]

Rubb Ed wrote:

Here's another way to look at it (again, we have to assume all 3 princes are perfectly logical in their actions):

[color=white]There are 7 possible cases for the crown combinations, with R for ruby and S for sapphire:
  1. RRS
  2. RSR
  3. SRR
  4. RSS
  5. SRS
  6. SSR
  7. SSS

All 3 open their eyes, and being perfectly logical, if any of cases 1-3 were the case, there'd be an immediate call of "Sapphire" by the sapphire wearer, and they'd win. All 3 of them know this, so all 3 know that, as no immediate call has happened, cases 1-3 are incorrect.

Cases 4-6 are exactly the same as cases 1-3, except reversed for the ruby. All any of the princes would have to do is see 1 ruby, and they'd immediately know they had a sapphire on their head. So, while delayed, there'd be a fast response of "Sapphire!" by someone if cases 4-6 were the case. The only screwed prince would be the one with the ruby, as he would never have enough information to determine his gem. Since there still hasn't been a call, they'll knock cases 4-6 out.

Since, at this point, cases 1-6 have been discarded, it winds up that each of the perfectly logical princes just has to go through the mental gymnastics faster than his brothers in order to be the one to realize only one case exists, #7, and thus he has a sapphire on his crown.[/color]

I still don't buy this, because I think it presupposes irrational confidence or fails to take into consideration the risk of being wrong. Or maybe it's more because I don't know how long a "perfectly rational" hesitation takes.

Anyway, think about the consequences. If you have an emerald:
1) You correctly claim to have an emerald: You'll be king
2) Nobody claims anything: You're all banished.

But if you have a ruby:
3) You wrongly claim to have an emerald: You're killed.
4) You keep your mouth shut and someone else gets it right: You're a lazy aristocrat for the rest of your life.
5) Everyone keeps their mouth shut: You're all banished.
6) You somehow figure out that you have a ruby (speak first when that knowing grin starts on your brother's face or guess well) and get crowned king. Your dad is pretty pissed off that his clever plan to screw you didn't work out.

Wordsmythe, your problem is that you're thinking like a writer. You're seeing the human element in a mathematical equation.

I never really considered what would happen to the other two princes if the third got the question wrong. I don't know if that's important, but it would be funny if the other two princes got to trade off the kingdom every three days or something

I could settle for a lazy aristocrat. The riddle is hard but on paper it makes sense, but if it ever happen in real life they would more then likely just not say a word, as you have to trust the other guys when they do not say a word. I would keep a straight face and let the other two speak and then win by default.

Next, the light bulb problem.

You are in a closed facility that consists of three, windowless rooms. The first room has three light switches, labeled A, B and C. The second room is a small corridor, which serves as a pressurization chamber between the first and third rooms. The third room is empty save for three incandescent light bulbs hanging from a low ceiling. These bulbs are labeled 1, 2 and 3 and are connected to the switches in the first room, but which switch connects which bulb is unknown. The bulbs in the third room are not turned on (The switches start in the off position). There is no way to see room 1 from room 3 and no way to see room 3 from room 1.

You start out in the first room and may flip the three switches in any manner you see fit, and may stay in this room as long as you feel necessary. Once you enter the pressure chamber, you cannot return to the first room; you may only proceed to the third room.
Given these rules, how can you determine which switch connects to which light bulb?

[color=white]First, flip switches A and B to the on position and wait ten minutes. Turn off switch B and quickly proceed to the third room. Whichever light is still on connects to switch A, as that is the switch you left on. Now feel each of the remaining light bulbs. The warm light bulb connects to switch B, which you had left on for ten minutes. The cold light bulb connects to switch C, since you never turned it on. [/color]

I've heard an alternate solution to this one.

[color=white]Since you can spend as long as you want in the first room, you spend a few days, weeks, years, whatever flipping C switch constantly on and off. Then flip the A switch and walk through to room 3. The light bulb that's on is A, light bulb that's off is B, and the light bulb that's burned out is C.

[/color]

adam.greenbrier wrote:

Wordsmythe, your problem is that you're thinking like a writer. You're seeing the human element in a mathematical equation.

Or I'm thinking like a professional risk manager. If you don't see two rubies, keeping your mouth shut seems to have the best risk/reward ratio.

wordsmythe wrote:
adam.greenbrier wrote:

Wordsmythe, your problem is that you're thinking like a writer. You're seeing the human element in a mathematical equation.

Or I'm thinking like a professional risk manager. If you don't see two rubies, keeping your mouth shut seems to have the best risk/reward ratio.

Usually, the way this is presented is that the one who gets it right lives, and everyone else dies. If no one gets it right in a span of time, they all die. Thus, the impetus to keep your mouth shut is pretty low, since you're dead unless you figure it out.

Anyhow... logic puzzle, not real life.

Complete next two letters of the sequence:

STNDRD--

I'll leave this be without a solution for now, because it's fairly easy.
(It stumped me, but that isn't saying much.)