Re: [buffywantswillow] FF Wonderful days...glorious nights (4/?)

[sbooth@xxxxxxxxxxxxxxxxxx]

On Wed, 20 Sep 2000 09:28:46 EDT, you wrote:

>Don't hurt your brain...heh...she might not even be from the show.LOL
>Shyfox
>>
>>Love it. I'm desparately racking my brain for who's got violet
>>coloured eyes.
>>


Hmm. That implies that she might be. Or she could be from
another show or even a book and we're looking at a crossover
here. IIRC Gabrielle DeLioncourt had violet eyes.

As for hurting my brain I've already done that today. They've
recently launched a department newsletter and on the back it had
a brain teaser, a logic problem (supposedly). Which was
something like this.

4 people are captured by a gun man and buried up to their necks
(ie so just their heads are above the ground). Each is wearing a
hat on their head and they are told that there are two black hats
and two white hats. They have 5 minutes to work out what colour
hat they are wearing when asked they must answer and if they give
the wrong answer they will be shot, if they don't answer they
will be shot but if they give the right answer they won't be shot
and will be let go. They cannot turnaround or talk to each
other. They are arranged as follows (for ease of description
they are persons A through D) in a line:

*Between A and B there is a solid brick wall that cannot be seen
through.  

*Person A is facing the wall and cannot see any of the other
people. Person A is wearing a black hat.

*Person B is facing the wall (from the other side) and cannot see
anyone. Person B is wearing a white hat.

*Person C is facing the wall and is immediately behind person B,
they can see the back of Person Bs head and Person Bs hat.
person C is wearing a black hat.

*Person D is facing the wall and can see the back of person Cs
head and both person Cs and person Bs hats. Person D is wearing
a white hat.

*No-one can see their own hat.

*There are no reflective surfaces in which they could see their
own hat or the hat of a person behind them or on the opposite
side of the wall to them.

The question is who is 100% sure what colour their hat is and
why. There is no trick, it is 100% logic. the question contains
all of the information required to answer the question.

Below, after some space is the answer given by the person who
created it and why. Also why it is the wrong answer following
the information given.

1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
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9
0
1
2
3
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9
0

The Official answer is that person C will be 100% sure as to the
colour of their hat (black). The explanation is that they can
see that person A is wearing a white hat and will believe that
the gunman will have made sure that no-one could see 2 hats of
the same colour.

This answer is wrong because it requires an assumption, and
deduction based on an assumption cannot have 100% degree of
confidence.

There are two answers which are acceptable logically based on the
question as given.

1) The wording of the question does not explicitly limit the who
to being one of the 4 so the who could be the gunman who can see
all 4 people and who put the hats on them. This is unsafe it
relies on the poor grammer of the question setter.

2) The last person to be asked will know by a simple matter of
elimination by paying attention to what people answer and what
happens to them. If a person answers white and gets shot them
clearly they were wearing black so there's one less black hat
about and visa versa.


Stephen
-- 
Stephen Booth, Data Integration Specialist & Spoiler Slut
"I may be fat ugly and bald but... OK, fairpoint" - Me
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