Author
Message
monkeytroll
Boot
Joined: 23 Oct 2005 Posts: 33
#174 - Purple -Jaunty Paul JAUNTY PAUL Game Card
In a Perplex City gameshow hosted by Jaunty Paul, you're presented with 3 doors. Behind one of the doors is a yacht, and the other two doors hide goats. Imagine you pick door A . Before you open it, Jaunty (who knows where everything is) steps in and opens up door C , which has one of the goats behind it. He then asks you, "Are you absolutely sure you want to stick with your choice, or do you want to switch to door B ?"
What is the probability that you'll get the yacht if you stay with door A, and what's the probability if you switch to door B?
Puzzle set by Tippy
Map on back shows Osiris Road, Shiran Lane, Shone Street, Ascent Lane, Descent Lane and Gear Design building
_________________"I have not failed. I've just found ten thousand ways that don't work." Thomas Edison (unless he stole it from Tesla)
Posted: Thu Nov 24, 2005 5:30 pm
Atrophied
Entrenched
Joined: 29 Aug 2004 Posts: 1133 Location: 53742E 4A6F686E27732C 4E4C00
Um.. if you get it wrong, do you get killed by a sock-puppet?
Seriously though, the odds are still 50:50 no matter what anyone else tries to tell you.
Oh, and what are the chances of getting scans of these cards (and their backs) at 60dpi resolution?
_________________"It will be happened; it shall be going to happening; it will be was an event that could will have been taken place in the future." -- Time travel, as explained by Arnold J. Rimmer
"The Future's bright, the Future's Cuboid" - Juxta
Posted: Thu Nov 24, 2005 6:03 pm
monkeytroll
Boot
Joined: 23 Oct 2005 Posts: 33
Still having fun & games with my scanner I'm afraid. Hence I've only posted those cards that don't need the image to solve. Please bear with me, to be honest I'm not sure what I'm doing either which probably isn't helping.
Spoiler (Rollover to View):
The solve page asks for x/y format and 1/2 gets an incorrect- along with a message that says : Close, here's a clue- Hard to believe, but that's not the answer!
_________________"I have not failed. I've just found ten thousand ways that don't work." Thomas Edison (unless he stole it from Tesla)
Posted: Thu Nov 24, 2005 6:30 pm
European Chris
Unfictologist
Joined: 19 Jul 2005 Posts: 1264 Location: London's trendy Whitechapel
_________________
http://www.hayfestival.com/archive/2006/05/blasphemy-debate.aspx
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Posted: Thu Nov 24, 2005 6:36 pm
ZoomZoom
Boot
Joined: 12 Nov 2004 Posts: 21 Location: Cambridge, UK
Spoiler (Rollover to View):
Door A = 1/3, Door B = 2/3
Door A has a 1/3 chance of having the yacht behind it. This doesnt change when the other door is opened.
B & C have a 2/3 chance together. You ae shown that C = 0. Therefore B = 2/3.
Posted: Thu Nov 24, 2005 6:38 pm
cassandra
Entrenched
Joined: 25 Mar 2005 Posts: 831
didn't we play this one in Receda's Revenge?
Posted: Thu Nov 24, 2005 7:48 pm
sixsidedsquare
Unfettered
Joined: 24 Mar 2005 Posts: 409 Location: 60E
Yeah, and I knew those dang school kids had it wrong
Posted: Thu Nov 24, 2005 9:05 pm
Kvasir
Boot
Joined: 15 Oct 2005 Posts: 48
ZoomZoom wrote:
Spoiler (Rollover to View):
Door A = 1/3, Door B = 2/3
Door A has a 1/3 chance of having the yacht behind it. This doesnt change when the other door is opened.
B & C have a 2/3 chance together. You ae shown that C = 0. Therefore B = 2/3.
That so doesn't seem right.
Spoiler (Rollover to View):
For the simple reason that by the same logic, at the outset Door B = 1/3, so A & C have a 2/3 chance together, you are shown that C=0 therefore A=2/3...
Having read up on this I can see that my instincts must be wrong, but it still doesn't feel right...
Posted: Sun Nov 27, 2005 11:07 am
EvilOverlord
Greenhorn
Joined: 02 Dec 2005 Posts: 6 Location: Ann Arbor, MI, US
It makes more sense if you think of it this way:
Instead of 3 doors, there are 1000. Only one door has a yacht behind it and the rest have goats. You pick Door 1. Jaunty shows that Doors 2 - 728 and Doors 730 - 1000 have goats behind them.
Would you stick with Door 1, or choose Door 729?
You only have a 1/1000 chance of getting it right on the first guess. In all the other 999/1000 cases, Jaunty will reveal all the doors except the one that the yacht is behind (and the one you chose, which has a goat). Thus, you have a 999/1000 chance of getting the yacht if you switch.
You can be sure that the show will go off the air soon - either from losing so much money from practically giving away yachts, or from lawsuits after you are trampled by 999 goats.
If there are only 3 doors, the situation is analogous, only not so obvious, and with worse odds (2/3).
Posted: Fri Dec 02, 2005 10:44 pm
doublecross
Unfettered
Joined: 25 Jul 2005 Posts: 588 Location: London, UK
This does seem counter-intuitive, but if you actually try it with someone, you will see that it is right.
_________________xx
Posted: Sat Dec 03, 2005 6:58 am
jojojojo
Decorated
Joined: 10 Dec 2005 Posts: 208 Location: Where the puffins fly, and the sheep roam.
I wouldn't feel too bad if you originally thought the odds were 50:50.
The original problem was sent to a newspaper column, in 1990, called "Ask Marilyn" in an American Magazine called Parade. People sent in problems/puzzle to the column writer Marilyn vos Savant who, at the time, had the highest IQ recorded in the Guiness Book of records.
Marilyn gave the correct solution.
Many mathematicians disagreed with Marilyn, and many members of the public complained. 92% of letters she received said that she was wrong. and to quote one such remark:
Quote:
You are utterly incorrect... how many irate mathematicians are needed to get you to change your mind?
E.Ray Bobo, Ph.D., Georgetown University.
And currently, it is still debated. There is a complicated formula I can provide you with if you like, but the easiest way to understand it is to draw out all the possible outcomes. (Which I can also draw out for you if you like, but I don't know how to put images in a spoiler or even know if you can!)
How do I know all this? I read "The Curious Incident of the Dog in the Night-Time" by Mark Haddon. Very good book!
_________________For the record I have one head!
Posted: Thu Dec 15, 2005 8:53 am
Dickie911
Greenhorn
Joined: 29 Dec 2005 Posts: 7 Location: Bristol UK
Jojojo
all you have to do is write the text you want to hide in the text box.
Spoiler (Rollover to View):
Then higlight it by selecting the section of text you want to hide and then just click the Spoiler box above the box.
You will then see the html code for spoiler at beginning and end of selected text.
Posted: Sat Dec 31, 2005 1:53 pm
wizzsteve2
Boot
Joined: 26 Feb 2006 Posts: 52 Location: The Murder Scene
can i get an answer to this plz ive tried 2 answers
Spoiler (Rollover to View):
a=1/3b=2/3 and a&b=2/3
and both failled so can i get an answer that works plz
_________________Love is the Red, The Rose, On you coffin door, WHats life like bleeding on the Floor?
Posted: Sun Mar 05, 2006 8:16 am
Dragon_Hogg
Kilroy
Joined: 08 Mar 2006 Posts: 2
solved the exepted answer is
Spoiler (Rollover to View):
Probability for Door A: 1/3
Probability for Door B: 2/3
but the propre answer is 50:50 or 1/2
cos you only get a choice of 2 doors
as 1 is always taken away so 1 door+goat
is taken away you only chose between the two left.
so (50+50+50)-50=100, stupid mathematicians.
Posted: Wed Mar 08, 2006 6:13 pm
forensick
Greenhorn
Joined: 26 Apr 2006 Posts: 9 Location: Macomb, IL
I think the biggest problem with this question is that it's
a) not made clear or
b) we just don't put it together
that the host is always going to show the other goat first.
He's not going to walk over and open the door with the car first (if you chose a goat). It's that logic that made the problem difficult for me.
Don't get me wrong, I'm still not a fan of the math behind it. I'd much rather accept 50/50 or even 66/50 before the "truth."
Posted: Fri Apr 28, 2006 2:19 pm
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