document.write( "Question 978502: In how many ways can a class of 20 pupils be split into two groups of 8 and 12,If there is two twins who can't be separated? \n" ); document.write( "

Algebra.Com's Answer #599928 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!
In how many ways can a class of 20 pupils be split into two groups of 8 and 12,If there is two twins who can't be separated?
\n" ); document.write( "

\r\n" );
document.write( "We only need to choose the group of 8, for the ones not chosen will make up the\r\n" );
document.write( "group of 12.\r\n" );
document.write( "\r\n" );
document.write( "Case 1: The set of twins are in the group of 8.\r\n" );
document.write( "\r\n" );
document.write( "We choose the other 6 in that group from the 18 non-twins in 18C6 ways. \r\n" );
document.write( "\r\n" );
document.write( "Case 2: The set of twins are NOT in the group of 8.\r\n" );
document.write( "\r\n" );
document.write( "We choose all 8 from the 18 non-twins in 18C8 ways.\r\n" );
document.write( "\r\n" );
document.write( "Answer: 18C6  + 18C8 = 18564 + 43758 = 62322 ways.\r\n" );
document.write( "\r\n" );
document.write( "Edwin

\n" ); document.write( "

\n" );