document.write( "Question 1159623: How many arrangements of the word ACTIVE are there if the C and E\r
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document.write( "a) must always be together?
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document.write( "b)must never be together? \n" );
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Algebra.Com's Answer #782757 by ikleyn(52778)![]() ![]() You can put this solution on YOUR website! . \n" ); document.write( " \r\n" ); document.write( "\r\n" ); document.write( "(a) If the C and E are always together, we can consider this pair as one merged object.\r\n" ); document.write( "\r\n" ); document.write( " Then we have 5 objects in total that admit 5! = 1*2*3*4*5 = 120 permutations.\r\n" ); document.write( "\r\n" ); document.write( " But the merged object has two states: CE and EC.\r\n" ); document.write( "\r\n" ); document.write( " By combining all these permutations, we have, in total, 2*5! = 2*120 = 240 permutations.\r\n" ); document.write( "\r\n" ); document.write( " It is the ANSWER in this case.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "(b) This time, we should consider all permutations of 6 letters of the word ACTIVE, 6! = 720 permutations, \r\n" ); document.write( "\r\n" ); document.write( " and subtract those 2*120 = 240 permutations, found in the case (a), where the letters C and E are placed together.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( " So, the ANSWER in this case is 6! - 2*5! = 720 - 240 = 480.\r\n" ); document.write( "\r \n" ); document.write( "\n" ); document.write( "Solved, answered, explained and completed.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-----------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "For many other similar solved problems, see the lesson\r \n" ); document.write( "\n" ); document.write( " - Problems on Permutations with restrictions \r \n" ); document.write( "\n" ); document.write( "in this site.\r \n" ); document.write( " \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 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The referred lesson is the part of this online textbook under the topic \"Combinatorics: Combinations and permutations\". \r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Save the link to this textbook together with its description\r \n" ); document.write( " \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 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "into your archive and use when it is needed.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |