Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Playing with numbers

  • To: mathgroup at smc.vnet.net
  • Subject: [mg50162] Re: Playing with numbers
  • From: kzhang at flashmail.com (Kezhao Zhang)
  • Date: Wed, 18 Aug 2004 01:20:14 -0400 (EDT)
  • References: <cfshq3$9qf$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

"Thomas Manz" <thomasmanz at web.de> wrote in message news:<cfshq3$9qf$1 at smc.vnet.net>...
> Hello!
> 
> Everyone of you knows number riddles! Here´s an example:
> you have five equations:
> (1) H - F = I
> (2) F x G = C
> (3) E / B = F
> (4) A + B = H
> (5) C - D = A
> every variable from A to I stands for a number from 1 to 9, where each number appears only once (no two variables can have the same value)!!
> 
> Solving this problem with a piece of paper and your brain should take not more than 10 minutes.
> (I tried it, and also found that 5-4-6-1-8-2-3-9-7 (A-I) is the ONLY solution!)
> 
> But how can I solve it with Mathematica??
> 
> best regards
> Thomas

Here is a way to solve it by brute force:

p=Permutations[Range[9]];
loc=Position[(And[h - 
  f == i, f g == c, e/b == f, a + b == h, c - d == a] /. Thread[{a, b, c, d,
             e, f, g, h, i} -> #]) & /@ p, True];
p[[loc[[1,1]]]

Indeed, there is only one solution.

K. Z.


  • Prev by Date: General expression of this definite integral ?
  • Next by Date: Re: Kriging code in Mathematica
  • Previous by thread: Re: Playing with numbers
  • Next by thread: Re:Playing with numbers