A puzzle for you to ponder

[ninebob]

With thanks to mildmanneredjanitor, whose site I found this on. Took me a good while but I now have it figured out.

Shown above are 4 men buried up to their necks in the ground.

They can not move so can only look forward.

Between A and B is a brick wall which can not be seen through.

They know that between them are 4 hats, 2 x black and 2 x white, but they do not know which colour they are wearing.

In order to avoid being shot ONE of them must call out to the executioner the correct colour of their hat. If they get it wrong, everyone will be shot.

They are not allowed to talk to each other and have 10 minutes to fathom it out.

After 1 minute:

Q Which one of them calls out ?

Q. Why is he 100% certain of the colour of his hat ?

This is not a trick question.

 

[AdamW]

I've got it!!!

Spoiler below
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If B and C had the same colour hat, D would shout out that his hat was a different colour to theirs.

C knows this.

As D does NOT shout out, he can not be certain as to the colour of his hat. Therefore, B and C have different colour hats.

C looks at B, sees he has a WHITE hat, therefore knows he MUST have a BLACK hat. He shouts out.

Yay!

 

[kendor]

nope, they cannot move and can only look forward so although they need to call out none of them can so they all get shot! A lives a bit longer as they have to knock a hole in the wall in order to shoot him

this is a rework of the riddle of in a darkroom how many socks do you need to pull out of a drawer of an equal number of black and white pairs in order to get a matching pair?
answer is?

 

[WoodYouLike]

That'll be 3

 

[ninebob]

Adam is right. How long did it take you, or did you go googling for a solution?

 

[felix]

Adam is right but with one proviso. C must assume that D is neither blind nor stupid - though under the circumstances that's an assumption worth making!

I must say that it's a bit hard on A and B, neither of whom stand a chance. Here's a variation in which all get a fair chance. There are three prisoners in a cell and the governor is feeling generous so he decides to let one go free; but which one shall it be? Here's how it goes.

"I have five sticky labels (don't get me started), two white and three black. Each man will get one label on the back of his head. The first man who can tell me the colour of his own label goes free."

With that he lines them up facing the wall and sticks a black label on each of them. They are then allowed to view each other's labels. Within five minutes one of them announces that he has a black label. The solution is along the same lines as the original puzzle.

 

[Big_Spark]

Perhaps they just tipped the hat off their head and then shouted

(I know it is not the right answer)

 

[AdamW]

Adam is right. How long did it take you, or did you go googling for a solution?

I was impressed with myself. I took a piece of paper and two different coloured pens. I then started to write down a list of what each person could assume. Struck it in about 3 minutes. No googling required!

 

[jtaunton]

I was going to say C, but for a different reason....

As they are buried up to their neck in the sand, it stands to reason that they are somewhere sunny

As C is wearing a black hat, his head will start getting hot after a minute, whilst he watches B hardly breaking a sweat

And the wall kind of stops the sun getting to A. Or something.

 

[AdamW]

Hehe, creative thinking, I like it!

Here's one for you. I have embellished it a little, mind!

A king is to hold a banquet, at which he will serve his prized wine of which only 1000 bottles were ever made. However, the day before the banquet his men discover 10 anti-royalists in his wine cellar. They admit to having poisoned ONE bottle, but will never reveal which one it is (perhaps they are like, ultra-hard ninja terrorists or something).

The king is distraught. He MUST serve that wine at his banquet, but he cannot risk poisoning one of his guests. So, he decides to use those 10 of his enemies to discover which bottle is poisoned.

Now for the rules:

1) any prisoner can sample any number of bottles. If you wish, you can have them all try all 1000 bottles.

2) The poison takes 24 hours to become apparent, and he only has 25 hours until the banquet.

How does the king go about determining the poisoned bottle?

 

[Igorian]

I've seen this before, but won't spoil it.

As a clue, you have to think like a computer.

 

[petewood]

my brain just crashed

 

[Igorian]

my brain just crashed

Is it in bits then?

 

[jtaunton]

Eh ? Is this some binary thing ?

Do the baddies know which is the spoilt wine ? Are they averse to dying for the cause ? Did they not have to open the bottle with a corkscrew and stick the cork back in, or does the king favour screw-top ?


Whilst I await the answers, an explorer leaves his camp, marches a mile south and spies a bear. He chases the bear a mile east, shoots and kills it, then carries it the mile north back to his camp. What colour is the bear ?

 

[breezer]

What colour is the bear ?

fred?