Solve - takes very long time

• To: mathgroup at smc.vnet.net
• Subject: [mg121804] Solve - takes very long time
• From: Fredob <fredrik.doberl at gmail.com>
• Date: Mon, 3 Oct 2011 04:21:54 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com

```Hi,

I tried the following on Mathematica 8 and it doesn't seem to stop
running (waited 40 minutes on a 2.6 Ghz processor w 6 GB of primary
memory).

Solve[
{100*Subscript[x, 2] + 10*Subscript[x, 1] + Subscript[x, 0] +
100*Subscript[y, 2] + 10*Subscript[y, 1] + Subscript[y, 0] ==
100*Subscript[z, 2] + 10*Subscript[z, 1] + Subscript[z, 0],
Subscript[x, 0] > 0, Subscript[y, 0] > 0, Subscript[z, 0] > 0,
Subscript[x, 1] > 0, Subscript[y, 1] > 0, Subscript[z, 1] > 0,
Subscript[x, 2] > 0, Subscript[y, 2] > 0, Subscript[z, 2] > 0,
Subscript[x, 0] <= 9, Subscript[y, 0] <= 9, Subscript[z, 0] <= 9,
Subscript[x, 1] <= 9, Subscript[y, 1] <= 9, Subscript[z, 1] <= 9,
Subscript[x, 2] <= 9, Subscript[y, 2] <= 9, Subscript[z, 2] <= 9,
Subscript[x, 0] != Subscript[y, 0] != Subscript[z, 0] != Subscript[
x, 1] != Subscript[y, 1] != Subscript[z, 1] != Subscript[x, 2] !=
Subscript[y, 2] != Subscript[z, 2]},
{Subscript[x, 2], Subscript[y, 2], Subscript[z, 2], Subscript[x, 1],
Subscript[y, 1], Subscript[z, 1], Subscript[x, 0], Subscript[y, 0],
Subscript[z, 0] },
Integers]

The problem was a homework for my daugther where you are supposed to
use all digits to build - but only once - 2 three digit numbers and