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25 Jun 2003, 17:16
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#1
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Probability Question
This is the question I liked the most from my STEP exam today.
Feel free to discuss it, or whatever.
13.
In a rabbit warren, underground chambers A, B, C and D are at the vertices of a square, and burrows join A to B, B to C, C to D and D to A. Each of the chambers also has a tunnel to the surface. A rabbit finding itself in any chamber runs along one of the two burrows to a neighbouring chamber, or leaves the burrow through the tunnel to the surface. Each of these three possibilities is equally likely.
Let pa, pb, pc and pd be the probabilities of a rabbit leaving the burrow through the tunnel from chamber A, given it is currently in chamber A, B, C or D, respectively.
(i) Explain why pa = 1/3 + (1/3)pb + (1/3)pd.
(ii) Determine pa.
(iii) Find the probability that a rabbit which starts in chamber A does not visit chamber C, given that it eventually leaves the burrow through the tunnel in chamber A.
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25 Jun 2003, 17:18
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#2
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Why were you doing a STEP exam?
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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25 Jun 2003, 17:24
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#3
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by Proteus
Why were you doing a STEP exam?
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Doing STEP II and III so they can't argue with me changing to Maths.
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25 Jun 2003, 17:26
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#4
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Quote:
Originally posted by MrL_JaKiri
Doing STEP II and III so they can't argue with me changing to Maths.
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Oh.
Sounds fun.
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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25 Jun 2003, 17:28
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#5
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by Proteus
Oh.
Sounds fun.
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I did III today, so the easy one's on Friday.
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25 Jun 2003, 17:29
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#6
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Why are you changing to Maths?
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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25 Jun 2003, 17:31
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#7
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by Proteus
Why are you changing to Maths?
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No practicals, half the number of supervisions.
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25 Jun 2003, 17:35
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#8
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Quote:
Originally posted by MrL_JaKiri
No practicals, half the number of supervisions.
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That sounds like a very good reason.
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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25 Jun 2003, 17:39
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#9
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Gubbish
Join Date: Sep 2000
Location: #FoW
Posts: 2,323
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Drunken walks are fun
err, that should be random walks shouldn't it?
__________________
Gubble gubble gubble gubble
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25 Jun 2003, 18:09
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#10
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Cute and cuddly
Join Date: Jul 2002
Location: New York
Posts: 1,891
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Quote:
Originally posted by Proteus
That sounds like a very good reason.
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oi i went to trinity on monday it was nice you posh git. there was a crazy woman at the Wren library entrance though
__________________
"You're a ****ing ugly bitch. I want to stab you to death, and then play around with your blood."
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25 Jun 2003, 18:13
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#11
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Quote:
Originally posted by Bloomers III
oi i went to trinity on monday it was nice you posh git. there was a crazy woman at the Wren library entrance though
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Everyone who works in the Library is crazy.
And yes, Trinity is nice.
__________________
Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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25 Jun 2003, 20:08
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#12
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Banned
Join Date: Apr 2002
Posts: 337
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I don't like "Probability Question". Probability has nothing to do with math or science, it's all matter of luck.
Sadly, there is absolutely nothing rabbit can do to improve his luck. In fact, there's nothing anybody can to to improve their luck. At least not without tearing asunder the very fabric of the Universe.
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25 Jun 2003, 20:31
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#13
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It was a Stupid Dream
Join Date: Jun 2002
Location: Winchester, UK
Posts: 2,077
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Quote:
Originally posted by Proteus
Everyone who works in the Library is crazy.
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Quote:
My faince from yesterday
I got a job in a library!
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yup
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25 Jun 2003, 20:33
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#14
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Gubbish
Join Date: Sep 2000
Location: #FoW
Posts: 2,323
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Quote:
Originally posted by the dying puppy
I don't like "Probability Question". Probability has nothing to do with math or science, it's all matter of luck.
Sadly, there is absolutely nothing rabbit can do to improve his luck. In fact, there's nothing anybody can to to improve their luck. At least not without tearing asunder the very fabric of the Universe.
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Eh, surely the rabbit can go wherever he wants? How is his movements determined by luck?
__________________
Gubble gubble gubble gubble
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25 Jun 2003, 20:45
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#15
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WHY DID YOU PUSH GRANDMA
Join Date: May 2003
Posts: 400
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The rabbit has already chosen his path. There is only one answer fools.
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25 Jun 2003, 21:00
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#16
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Vermin Supreme
Join Date: Jul 2000
Location: Pittsburgh
Posts: 3,280
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Quote:
Originally posted by huh
The rabbit has already chosen his path. There is only one answer fools.
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The question is, would the rabbit still have gone out at A if I hadn't said anything?
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25 Jun 2003, 21:16
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#17
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by huh
The rabbit has already chosen his path. There is only one answer fools.
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But we don't know it.
Empirically, it's the same.
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25 Jun 2003, 21:47
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#18
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Banned
Join Date: Apr 2002
Posts: 337
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Quote:
Originally posted by W
Eh, surely the rabbit can go wherever he wants? How is his movements determined by luck?
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sure he can go wherever he wants, but where he ends up to be is up to his "luck".
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25 Jun 2003, 21:52
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#19
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Gubbish
Join Date: Sep 2000
Location: #FoW
Posts: 2,323
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Quote:
Originally posted by the dying puppy
sure he can go wherever he wants, but where he ends up to be is up to his "luck".
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Nonsense, where he ends up is up to his actions. "Oh gee, I was lucky that I bought that burger!"
__________________
Gubble gubble gubble gubble
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25 Jun 2003, 21:57
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#20
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by the dying puppy
sure he can go wherever he wants, but where he ends up to be is up to his "luck".
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You're talking rubbish.
Get out of my thread.
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25 Jun 2003, 22:04
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#21
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Banned
Join Date: Apr 2002
Posts: 337
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Quote:
Originally posted by W
Nonsense, where he ends up is up to his actions. "Oh gee, I was lucky that I bought that burger!"
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"Ohh gee, I'm so lucky that after choosing chamber A, I end up in shiny chamber B, just where I wanted to be"
See?
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25 Jun 2003, 22:08
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#22
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by the dying puppy
"Ohh gee, I'm so lucky that after choosing chamber A, I end up in shiny chamber B, just where I wanted to be"
See?
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I told you to GET OUT OF MY THREAD
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25 Jun 2003, 22:09
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#23
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Banned
Join Date: Apr 2002
Posts: 337
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Quote:
Originally posted by MrL_JaKiri
You're talking rubbish.
Get out of my thread.
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I have a comment on that too, but I will have to get back to you later on that one.
See, you are very lucky Al, luck. Because unfortunately I have to leave right now..
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25 Jun 2003, 22:13
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#24
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Me
Join Date: Jun 2003
Location: At a computer
Posts: 21
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I have had nightnmares about maths questions like that
__________________
Its not What You Know, Its who you Know
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26 Jun 2003, 00:41
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#25
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WHY DID YOU PUSH GRANDMA
Join Date: May 2003
Posts: 400
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I was quite sure I made a second reply to this thread.
anger++
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26 Jun 2003, 10:18
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#26
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cynic
Join Date: May 2000
Location: Bishop Auckland Co. Durham
Posts: 8,809
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Quote:
Originally posted by Proteus
Everyone who works in the Library is crazy.
And yes, Trinity is nice.
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anyone who works in any library is crazy, trust me, i know cos thats my job \o/
__________________
lazy
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26 Jun 2003, 17:18
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#27
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Banned
Join Date: Apr 2002
Posts: 337
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I guess MrL_JaKiri aren't so lucky today. He still without the answer to his very unlucky question.
Better luck next life!
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26 Jun 2003, 17:30
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#28
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Gubbish
Join Date: Sep 2000
Location: #FoW
Posts: 2,323
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Quote:
Originally posted by the dying puppy
I guess MrL_JaKiri aren't so lucky today. He still without the answer to his very unlucky question.
Better luck next life!
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Eh? You mean he didn't answer this question on his examn? Why do you think so? Of course he has the answer, he's not stupid like you.
__________________
Gubble gubble gubble gubble
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26 Jun 2003, 18:12
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#29
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Banned
Join Date: Apr 2002
Posts: 337
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Quote:
Originally posted by W
Eh? You mean he didn't answer this question on his examn? Why do you think so? Of course he has the answer, he's not stupid like you.
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I'm sure he did answer on his question on exam, but nobody answerd his question in here.See?
p.s. I'm not stupid! I'm special.
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26 Jun 2003, 18:58
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#30
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Gubbish
Join Date: Sep 2000
Location: #FoW
Posts: 2,323
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Quote:
Originally posted by the dying puppy
I'm sure he did answer on his question on exam, but nobody answerd his question in here.See?
p.s. I'm not stupid! I'm special.
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It wasn't his question at all. And why would anyone answer it?
__________________
Gubble gubble gubble gubble
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26 Jun 2003, 19:01
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#31
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by the dying puppy
I guess MrL_JaKiri aren't so lucky today. He still without the answer to his very unlucky question.
Better luck next life!
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I posted it so people who like this kind of thing could attempt it, not to see if I got it right.
I know I got it right.
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26 Jun 2003, 19:02
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#32
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share the <3
Join Date: Aug 2001
Location: Location: Location:
Posts: 2,709
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oi look at your pms
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26 Jun 2003, 19:07
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#33
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Banned
Join Date: Apr 2002
Posts: 337
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Quote:
Originally posted by W
It wasn't his question at all. And why would anyone answer it?
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Oh, I don't know, I haven't read the whole thing. Complicated things always hurting my brain, so I don't even bother read 'em.
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26 Jun 2003, 19:17
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#34
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Banned
Join Date: Apr 2002
Posts: 337
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Seriously though, MrL can you explain how it works?
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26 Jun 2003, 19:21
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#35
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by Nusselt
oi look at your pms
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Replied.
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26 Jun 2003, 19:21
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#36
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by the dying puppy
Seriously though, MrL can you explain how it works?
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I can.
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26 Jun 2003, 19:23
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#37
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Ball
Join Date: Oct 2001
Posts: 4,410
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I get:
(i) it's obvious
(ii) 7/15
(iii) 45/49
Not checked though.
I didn't do this question, and I didn't do well at all . How did you do?
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26 Jun 2003, 19:24
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#38
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Banned
Join Date: Apr 2002
Posts: 337
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Quote:
Originally posted by MrL_JaKiri
I can.
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I want to know.
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26 Jun 2003, 19:27
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#39
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Quote:
Originally posted by queball
I get:
(i) it's obvious
(ii) 7/15
(iii) 45/49
Not checked though.
I didn't do this question, and I didn't do well at all . How did you do?
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i yes
ii no
iii no
I did 1, 3, 5, 7, 8 (I don't like the mechanics one, so I gave up doing all the odd numbers) and 13.
II tomorrow!
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27 Jun 2003, 11:44
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#40
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∞+♪˛
Join Date: Nov 2000
Location: :uo!te]oŻ|
Posts: 428
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Code:
| 0 | | 0 1/3 0 1/3 0 0 0 0 |∞ | 1 |
| 0 | | 1/3 0 1/3 0 0 0 0 0 | | 0 |
| 0 | | 0 1/3 0 1/3 0 0 0 0 | | 0 |
| 0 | = | 1/3 0 1/3 0 0 0 0 0 | * | 0 |
| pa | | 1/3 0 0 0 1 0 0 0 | | 0 |
| pb | | 0 1/3 0 0 0 1 0 0 | | 0 |
| pc | | 0 0 1/3 0 0 0 1 0 | | 0 |
| pd | | 0 0 0 1/3 0 0 0 1 | | 0 |
__________________
Structural Integrity for Creator - since he'll probably make PA turn 3D.
Wikipedia forum
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