document.write( "Question 886310: Twenty people decide to play softball. In how many ways can the 20 people be divided into 2 teams of 10 people?
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Algebra.Com's Answer #539530 by Edwin McCravy(20054) $\"\"$ $\"About$

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document.write( "Let the players be numbered 1 to 20.\r\n" );
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document.write( "First we think of there being two teams, Team A and Team B\r\n" );
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document.write( "We choose the players for team A in C(20,10) ways, or 184756, \r\n" );
document.write( "and the remaining 10 will be on team B.\r\n" );
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document.write( "But this is too many because, for instance, the 184756 counts\r\n" );
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document.write( "Team A = {2,5,6,9,11,14,15,16,18,20)\r\n" );
document.write( "Team B = {1,3,4,7,8,10,12,13,17,19}\r\n" );
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document.write( "and this\r\n" );
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document.write( "Team A = {1,3,4,7,8,10,12,13,17,19}\r\n" );
document.write( "Team B = {2,5,6,9,11,14,15,16,18,20)\r\n" );
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document.write( "as 2 different choices, but they are not.  Therefore we\r\n" );
document.write( "must divide the 184756 by 2!\r\n" );
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document.write( "Answer: 92378\r\n" );
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document.write( "Edwin

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