Math Is Fun Forum

bryan

Member

Registered: 2006-05-24

Posts: 4

tough one

you have to get heat water and eletric to each house but no lines can cross

heat                      water                    eletric

house 1                        house2                          house3

you can use a infinte amount of paper

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: tough one

Heehee, I do decision maths so I can prove that that's impossible. =P

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Why did the vector cross the road?
It wanted to be normal.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: tough one

Okay, I’ve been looking at some of these very old threads here …

And I’ve seen this puzzle before. Here is the solution:
http://puzzles.nigelcoldwell.co.uk/twentysix.htm

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: tough one

I think that is a cheap way out.  Represent each house as a vertex.  Now try it.

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: tough one

Then Euler’s formula comes into play.

http://en.wikipedia.org/wiki/Planar_gra … 7s_formula