Re: Re: Combinatorica questions!!!
- To: mathgroup at smc.vnet.net
- Subject: [mg20696] Re: [mg20606] Re: [mg20499] Combinatorica questions!!!
- From: "vmg" <vgerace at localnet.com>
- Date: Sun, 7 Nov 1999 02:10:23 -0500
- Organization: bCandid - Powering the world's discussions - http://bCandid.com
- References: <7vttl0$lk5$3@dragonfly.wolfram.com>
- Sender: owner-wri-mathgroup at wolfram.com
Moving the rook from these two positions is (at minimum) accomplished in only two moves, and a maximum of 14 if the piece traverses the diagonal route. Andrzej Kozlowski <andrzej at tuins.ac.jp> wrote in message news:7vttl0$lk5$3 at dragonfly.wolfram.com... > It does seem rather trivial when you look at it the right way. It would have > been easier to see if the problem referred the the king, not a rook :) > -- > > > > From: Rob Pratt <rpratt at email.unc.edu> > > Date: Tue, 2 Nov 1999 02:35:36 -0500 > > To: mathgroup at smc.vnet.net > > Subject: [mg20696] [mg20606] Re: [mg20499] Combinatorica questions!!! > > > > An approach to problem 1 that is simpler than those already given is to > > recognize that each path consists of a sequence of 14 moves, 7 of them to > > the RIGHT one space and 7 of them UP one space. Hence a path is uniquely > > determined by specifying which 7 of the 14 moves are RIGHT (the rest are > > UP). We are choosing 7 objects from among 14 positions, so the answer is > > > > Binomial[14,7]=3432 > > > > Rob Pratt > > Department of Operations Research > > The University of North Carolina at Chapel Hill > > > > rpratt at email.unc.edu > > > > http://www.unc.edu/~rpratt/ > > > > On Wed, 27 Oct 1999, Keren Edwards wrote: > > > >> Hi all!! > >> > >> 2 different questions: > >> > >> 1. how many ways does a castle have to reach from the bottom left side > >> corner > >> of a chess board to the upper right corner of the board if he can > >> move right > >> and up only? > >> > >> > >> > >> 2. you have 8 red identical balls, 9 purple identical balls and 7 white > >> identical ones. > >> a. How many ways can you choose 10 balls with no matter to the > >> order of the balls? > >> b. How many ways can you choose 10 balls with no matter to the > >> order of the balls, if each color must > >> be chosen once at least? > >> > >> > >> > >> Many thanx. > >> > >> > >> > >> > > > > > > > > > >