document.write( "Question 1116300: How many subsets of {m,a,t,h,r,o,c,k,s} contain exactly 5 elements? \n" ); document.write( "
Algebra.Com's Answer #731182 by ikleyn(52781)\"\" \"About 
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document.write( "The original set has 9 elements.\r\n" );
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document.write( "The number of 5-element subsets is the number of combinations  \"C%5B9%5D%5E5\" = \"%289%2A8%2A7%2A6%29%2F%281%2A2%2A3%2A4%29\" = 126.\r\n" );
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document.write( "Each subset of 5 elements is a combination of 9 items taken 5 at a time. \r\n" );
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document.write( "Each combination of 9 items taken 5 at a time is a subset of 5 elements.\r\n" );
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document.write( "Different subsets  <------> different combinations.\r\n" );
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\n" ); document.write( "\n" ); document.write( "On Combinations,  see the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Introduction to Combinations\r
\n" ); document.write( "\n" ); document.write( "    - PROOF of the formula on the number of Combinations\r
\n" ); document.write( "\n" ); document.write( "    - Problems on Combinations\r
\n" ); document.write( "\n" ); document.write( "    - OVERVIEW of lessons on Permutations and Combinations\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-II in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic  \"Combinatorics: Combinations and permutations\". \r
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\n" ); document.write( "\n" ); document.write( "Save the link to this textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-II
\n" ); document.write( "https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "into your archive and use when it is needed.\r
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