```Date: Feb 5, 2013 10:02 AM
Author: fom
Subject: Re: how many ways to pick two teams

On 2/5/2013 3:02 AM, quasi wrote:> fom wrote:>> William Elliot wrote:>>> G Patel wrote:>>>>>>> Is it 20 choose 10 or do I have to divide by 2?>>>>>>> What's it?>>>> What do you mean by picking teams?  Combinations are without>> regard to order,>>>> captains will try to make the best pick at each opportunity>> to choose...>>>> 20*18*16*14*12*10*8*6*4*2>>>> 19*17*15*13*11*9*7*5*3*1>> In the context of this problem, the only interest is in> determining the number of possible results for the two teams,> not in the mechanism by which the selection was performed.>> In particular, the order of selecting people doesn't matter.>> The intent of the problem is to find the number of possible> partitions of a 20-element subset into two 10-element subsets.The intent of the question was to ask how to solvea combination.  The stated problem was how tochoose teams.  Any kid who grew up playing sandlotbaseball knows the rules that formed the basisof my remark.  And, order does matter.  The kidswho are picked last are painfully aware of theirstatus.While I agree with you concerning the originalposter's interest (and sadly had not thoughtthat far before my own post), it may well bethat they would have been helped bymy observation under slightly differentcircumstances.  That is, they might havehad a need to at least consider the problemdifferently.Thank you, though.  I am so out of practicethat I find the assistance you give toothers quite interesting, even if it issometimes trivial to you.
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