What is the HARDEST riddle that you know?

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CPA

Elite Member
Nov 19, 2001
30,322
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<< Some riddles:

Three Dots
The King is about to die. He sends messengers throughout the land seeking for the 3 smartest people. Finally 3 are found. He gives them a task to see which one is the wisest. He tells them, "I will seat you in a triangle so that each of you faces the other two. Then I will blindfold you and paint either a red or a green dot on each of your foreheads. When I remove the blindfolds each of you must raise your hand if you see any green dots. As soon as you have figured out what color your own dot is, lower your hand and tell me." So he seats them, blindfolds them, and then paints a green dot on all three foreheads. When the blindfolds are removed, all three hands go up. After a long pause, one hand comes down and the man says, "Your highness, I have a green dot." How did he know?

Lying Defeated
You are visiting an island on which two tribes of natives live. One tribe has black soles and always lies; the other tribe has white soles and always tells the truth. There are three natives standing near you. You can't see the bottoms of their feet, and indeed you find out it is extremely rude to look at another's soles, but you are curious so you ask the first man, "Sir, what color are your soles?" Now he happens to understand English, but he can't speak it, so he replies in his native tounge, "Glub Glub". You turn to the second man and ask, "Sir, what did he say?" The second man replies, "He said he had white soles" Now to be sure, you turn to the third and ask, "Sir, what color of soles does this second man have?" The third man replies, "Sir, he has black soles." Now the question is, what color of soles does the third native have?

Crossing A Bridge
"U2" has a concert that starts in 17 minutes and they must all cross a bridge to get there. All four men begin on the same side of the bridge. You must help them across to the other side. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them. The flashlight must be walked back and forth, it cannot be thrown, etc. Each band member walks at a different speed. A pair must walk together at the rate of the slower man's pace :

Bono : 1 minute to cross
Edge : 2 minutes to cross
Adam : 5 minutes to cross
Larry : 10 minutes to cross
For example: if Bono and Larry across first, 10 minute have elapsed when they get to the other side of the bridge. If Larry then returns with the flashlight, a total of 20 minutes have passed and you have failed the mission.
Light Bulb Puzzle
There is a room with three light bulbs (in sockets). Outside the room there are three light switches which are connected to the bulbs inside the room, though you can't tell which switch is connected to which bulb. You can't see inside the room, and you're only allowed to go inside once. How do you find out which light switch is connected to which bulb?

Two Ropes
There are two uneven ropes that will take exactly an hour to burn each. These two ropes have different length. Now using these two ropes, you need to measure 45 minutes. You cannot assume that folding or burning half of a rope is 30 minutes since it is uneven, for example, it might take 30 minutes to burn 15% of one rope. How can you measure 45 minutes by using only these two ropes and a box of matches?

Ball-Bearing
A Supervisor in a Ball-Bearing factory receives a Memo from management saying that one of the 10 machines he manages is messing up, that machine is producing 9g bearings instead of 10g. The problem is that they don't know which machine is messing up. Management gave him a scale and they allowed him to use it only once to figure out the bad machine. How did he do it?

Hats
There are 3 black hats and 2 white hats in a box. Three men (we will call them A, B, & C) each reach into the box and place one of the hats on his own head. They cannot see what color hat they have chosen. The men are situated in a way that A can see the hats on B & C's heads, B can only see the hat on C's head and C cannot see any hats.
When A is asked if he knows the color of the hat he is wearing, he says no.
When B is asked if he knows the color of the hat he is wearing, he says no.
When C is asked if he knows the color of the hat he is wearing, he says yes and he is correct.
What color hat and how can this be?

Hourglasses
You have two hourglasses : a 4-minute glass and a 7-minute glass.
You want to measure 9 minutes.
How do you do it?
>>



Dammit B0mberman, give us the answers.

Though I think I know the hourglass one: Let the 7-minute glass empty completely and the 4-minute empty exactly half-way (though that might be tough to measure).
 

Murphyrulez

Golden Member
Mar 24, 2001
1,890
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<<
Ball-Bearing
A Supervisor in a Ball-Bearing factory receives a Memo from management saying that one of the 10 machines he manages is messing up, that machine is producing 9g bearings instead of 10g. The problem is that they don't know which machine is messing up. Management gave him a scale and they allowed him to use it only once to figure out the bad machine. How did he do it?

>>




Impossible??? You can only use the scale once? How can you compare anything with only one measurement?
 

CPA

Elite Member
Nov 19, 2001
30,322
4
0


<<

<<
Ball-Bearing
A Supervisor in a Ball-Bearing factory receives a Memo from management saying that one of the 10 machines he manages is messing up, that machine is producing 9g bearings instead of 10g. The problem is that they don't know which machine is messing up. Management gave him a scale and they allowed him to use it only once to figure out the bad machine. How did he do it?

>>




Impossible??? You can only use the scale once? How can you compare anything with only one measurement?
>>



Collect a bearing from each machine, label them 1-10 to correspond with the machine it came from, then add one at a time onto the scale. Once the scale reads n9 (n being the tenths digit variable), stop, and see which bearing was last placed on the scale. Seeing as you never remove previously placed bearings, the scaled has not been considered used, just in use.

Is that correct?
 

Hoeboy

Banned
Apr 20, 2000
3,517
0
0
<<Though I think I know the hourglass one: Let the 7-minute glass empty completely and the 4-minute empty exactly half-way (though that might be tough to measure). >>

that wouldn't be correct. i think the answer goes something like this. let's say the 4 minute hour glass is A and 7 minute one is B.

1) start both A & B hourglass
2) once A finishes up, there will be 3 minutes left in B.
3) start A again and once B finishes up it's final 3 minutes, there will be 1 minute left in A.
4) This is when you start timing. Once A finishes, you got one minute.
5) now reuse hourglass A again twice for an additional 8 minutes totaling to 9 minutes.
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81


<<

<<

<<
Ball-Bearing
A Supervisor in a Ball-Bearing factory receives a Memo from management saying that one of the 10 machines he manages is messing up, that machine is producing 9g bearings instead of 10g. The problem is that they don't know which machine is messing up. Management gave him a scale and they allowed him to use it only once to figure out the bad machine. How did he do it?

>>




Impossible??? You can only use the scale once? How can you compare anything with only one measurement?
>>



Collect a bearing from each machine, label them 1-10 to correspond with the machine it came from, then add one at a time onto the scale. Once the scale reads n9 (n being the tenths digit variable), stop, and see which bearing was last placed on the scale. Seeing as you never remove previously placed bearings, the scaled has not been considered used, just in use.

Is that correct?
>>


No, get one bearing from the first machine, two from the 2nd, three from the 3rd, and so on...then look at the combined weight :)
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81


<< Dammit B0mberman, give us the answers. >>


Oops, my fault :)

Should have checked back in here...
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81
Three Dots
The key to this is, oddly enough, the phrase After a long pause.

Let the 3 guys be named A, B, and C

If A saw a red dot on C and a green on B, he would know B would immediately be able to tell that he had a green dot on his forehead and would say so...since no one could figure it out after enough time for a "long pause," A knew that they all had green.
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81
Lying Defeated
Again, let them be named A,B, and C...

1) A says Glub Glub
2) B says A said "I have white soles"
3) C says B has black soles

If C has white soles, then B has black soles (3) and A said he has black soles (2)...but if he had black soles, then he'd say he has white (1)...and so forth. It's all messed up :confused:

If C has black soles, then B has white soles (3) and A said he has white soles (2)...all is well :)

 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81
Crossing A Bridge
Adam (5) and Larry (10) have to cross together. Otherwise, it's simple.

Bono (1) and Edge (2) cross together - 2 minutes gone
Bono returns - 3
Adam and Larry cross - 13
Edge returns - 15
Bono and Edge cross - 17
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81
Light Bulb Puzzle
This stumps a lot of people :)

Call the switches A, B, and C

Flick A on...leave it on for a minute then turn it off.
Flick B on

Go in the room. There should only be one lit bulb.
The lit bulb is B
The *warm* bulb is A
The cold bulb is C

I like that one. :D
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81
Two Ropes
Name the ropes A and B and they have ends x and y
At time 0, light Ax, Ay, and Bx
At time 30, rope A will burn out, light By
At time 45, rope B will burn out

Sort of confusing as there's different ways to interpret the riddle but it's fun nonetheless :)
 

crystal

Platinum Member
Nov 5, 1999
2,424
0
76
The rope thing is answered.

Light Bulb Puzzle
There is a room with three light bulbs (in sockets). Outside the room there are three light switches which are connected to the bulbs inside the room, though you can't tell which switch is connected to which bulb. You can't see inside the room, and you're only allowed to go inside once. How do you find out which light switch is connected to which bulb?

I assume you want to know about all three light switches connected to which bulbs.

1. Turn on first light switch for a while.
2. Turn off that one and turn on the second one.
3. Walk into the room, the lighted one is from the second light switch. Feel the other two bulbs, the warmed/hot bulb is from the first light switch. The cold light bulb is from the third light switch.

edited "I am too slow"
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81
Hats
Yucky is right ;)

If A saw 2 white hats, then he'd know he had a black on as there are no other white hats to wear
If A saw 1 white hat and 1 black, then he wouldn't know what hat color he had
If A saw 2 black hats, then he wouldn't know what hat color he had

Since he doesn't know, A sees at least 1 black hat.

Either B or C (That's the inclusive OR ;)) is wearing a black hat
If B sees a white hat on C, then he knows his hat is black
If B sees a black hat on C, then he wouldn't know what hat color he had

Therefore, C's hat is black
 

Hoeboy

Banned
Apr 20, 2000
3,517
0
0
Thanks for the riddles/answers bomberman. Here's one for everyone although it's somewhat easy.

There are 25 people sitting in an empty room. Everyone is sitting and can turn around but can't get up. Everyone is able to see EVERYTHING that is in the room. You have one apple. Where would you place the apple so that everyone can see it but one person?
 

b0mbrman

Lifer
Jun 1, 2001
29,470
1
81
Sure, it doesn't make sense, but the riddle does say "Everyone is able to see EVERYTHING that is in the room"
 

Hoeboy

Banned
Apr 20, 2000
3,517
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sure, catch me on a technicality :p here's another one that's really confusing:


You die and approach a fork in the road. One way leads to heaven, one leads to hell. You don't know which way is heaven or hell. There stands two person who knows the way. One of them always lie and the other one is always honest. You can ask EITHER of them ONLY ONE question. What question would you ask to find the way to heaven?
 

sheselectric

Golden Member
Mar 6, 2002
1,210
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0
this is a total guess because i think i've heard this one before. aren't you supposed to ask one what he would do if he was the other person? something like that. it hurts my brain. :)
 

Koing

Elite Member <br> Super Moderator<br> Health and F
Oct 11, 2000
16,843
2
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Heres a few cool riddles:

6 Eggs and 6 People Riddle:
There are 6 eggs in a basket. There are 6 people. Each person takes an egg. How is there one egg left in a basket?

Bus driver riddle.
You are walking along a street. You see a bus driver going down the street in the opposite direction in a one way street. You see the police opposite you. Why isn't the bus driver stopped or pulled over?

will post up answers when you guys sweat it out a bit more:D
 

MillionaireNextDoor

Platinum Member
Nov 16, 2000
2,918
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You enter a dark room with only one match. You are given the task of illuminating the whole room. To your left is a stove, to your right is a fireplace, and in the center is a candle. Which of these do you light first?






Ans:
The match.
 

MillionaireNextDoor

Platinum Member
Nov 16, 2000
2,918
1
0


<< 6 Eggs and 6 People Riddle:
There are 6 eggs in a basket. There are 6 people. Each person takes an egg. How is there one egg left in a basket?
>>



One person leaves with the basket along with his egg
 

Koing

Elite Member <br> Super Moderator<br> Health and F
Oct 11, 2000
16,843
2
0


<<

<< 6 Eggs and 6 People Riddle:
There are 6 eggs in a basket. There are 6 people. Each person takes an egg. How is there one egg left in a basket?
>>



One person leaves with the basket along with his egg
>>



ditto:)

Did you get the other one?