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        riddles >> medium >> Decanting Problem
        
(Message started by: checker on Nov 28th, 2006, 3:26am)
Title: Decanting Problem
Post by checker on Nov 28th, 2006, 3:26am
There where three jugs kept on table A,B and C with the capacities 8,5 and 3 litres respectively,but non are calibrated.Jug A is filled with 8 litres of wine.By a series of pouring back and forth among the three jugs,divide the 8 litres in jug A,and 4 in jug B
Title: Re: Decanting Problem
Post by towr on Nov 28th, 2006, 3:29am
What do you mean by "none are calibrated" ?
Title: Re: Decanting Problem
Post by Whiskey Tango Foxtrot on Nov 28th, 2006, 5:12am
I think he means none are graduated.  You can't just read the markings off the side.

Also, "divide the 8 litres in jug A,and 4 in jug B" doesn't make much sense.
Title: Re: Decanting Problem
Post by Three Hands on Nov 28th, 2006, 6:36am
Interpreting the riddle to be asking for Jug A being filled at the start (8 litres), and getting to a state where Jug B has exactly 4 litres of wine (and Jug A with the remaining 4 litres) through pouring between jugs, filling each jug that is being poured into, I get the following solution:

[hideb]Start: 8,0,0
A-B: 3,5,0
B-C: 3,2,3
C-A: 6,2,0
B-C: 6,0,2
A-B: 1,5,2
B-C: 1,4,3
(C-A: 4,4,0)[/hideb]

That's pretty much the best guess I have at what the riddle is asking for...
Title: Re: Decanting Problem
Post by THUDandBLUNDER on Nov 28th, 2006, 6:56am
Three Hands, how did you measure 1 litre in your penultimate step?    :o
Title: Re: Decanting Problem
Post by Three Hands on Nov 28th, 2006, 7:05am
Um, if C has a capacity of 3 litres, and already has 2 litres in it...

Granted, since I'm posting from Australia, it's a bit on the late side here, but I hoped I'd made the reasoning pretty clear...

An aside: OK, so technically I mis-worded my earlier post. Read "filling each jug that is being poured into" as "filling as far as possible each jug that is being poured into", since the method relies on this...
Title: Re: Decanting Problem
Post by THUDandBLUNDER on Nov 28th, 2006, 7:09am

on 11/28/06 at 07:05:25, Three Hands wrote:
Um, if C has a capacity of 3 litres, and already has 2 litres in it...

Silly me. Well, if the world chess champion can overlook a mate-in-one by a laptop computer...  ::)
http://chessbase.com/newsdetail.asp?newsid=3512

Anyway, these problems are best solved in general using something called trilinear coordinates.
http://www.cut-the-knot.org/ctk/Water.shtml

(You are not in Australia for the Ashes, are you?)
Title: Re: Decanting Problem
Post by Sameer on Nov 28th, 2006, 1:12pm

on 11/28/06 at 07:09:01, THUDandBLUNDER wrote:
(You are not in Australia for the Ashes, are you?)


Well England lost horribly in first test, what do you feel about second one!!
Title: Re: Decanting Problem
Post by THUDandBLUNDER on Nov 28th, 2006, 1:20pm

on 11/28/06 at 13:12:17, Sameer wrote:
Well England lost horribly in first test, what do you feel about second one!!

We will draw the next two Tests, then Vaughan will come back for the 4th, and we will win 2-1, just like last time!    
::)
Title: Re: Decanting Problem
Post by Three Hands on Nov 29th, 2006, 7:15am
Actually down in Australia for travelling around/seeing the world before finding a job and getting stuck in the "real" world. Don't have any tickets for the Ashes tests (I think they'd sold out long before I got here), but there is the advantage of not having to stay up until stupid o' clock in order to see how play is progressing, which is nice.
Title: Re: Decanting Problem
Post by mc2 on Nov 6th, 2007, 4:37pm
[hideb]fill three
pour into five
fill three
pour into five till full
leaves 1 in three
pour five into eight
pour 1 into five
fill three
pour into five[/hideb]
I think this may be short route.  I submit for dissection.[hide][/hide]
Title: Re: Decanting Problem
Post by ThudanBlunder on Nov 7th, 2007, 12:59pm

on 11/06/07 at 16:37:37, mc2 wrote:
pour five into eight

What happens to this five?   ::)
Title: Re: Decanting Problem
Post by SMQ on Nov 7th, 2007, 1:09pm

on 11/07/07 at 12:59:53, ThudanBlunder wrote:
What happens to this five?   ::)

???  Assuming that by "fill X" he always means "pour from 8 into X until full", the solution works out just fine, doesn't it?

--SMQ
Title: Re: Decanting Problem
Post by ThudanBlunder on Nov 7th, 2007, 5:14pm

on 11/07/07 at 13:09:02, SMQ wrote:
???  Assuming that by "fill X" he always means "pour from 8 into X until full", the solution works out just fine, doesn't it?
--SMQ

OK; I thought it was being filled from a tap.
Title: Re: Decanting Problem
Post by rmsgrey on Nov 8th, 2007, 7:00am

on 11/06/07 at 16:37:37, mc2 wrote:
I think this may be short route.  I submit for dissection.

That 9-move solution works. There is a 7-move solution which is shorter.


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