document.write( "Question 967697: April, Bill, Candace, and Bobby are to be seated at random in a row of 8 chairs. What is the probability that April and Bobby will occupy the seats at the end of the row?\r
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Algebra.Com's Answer #779720 by ikleyn(52794) $\"\"$ $\"About$

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document.write( "The total number of placing 4 persons in a row of 8 chairs is   = 8*7*6*5 = 1680.\r\n" );
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document.write( "    Here  represents the number of chosing chairs and 4! represents the number of all possible permutations \r\n" );
document.write( "    of 4 person inside the given claster of 4 chairs.\r\n" );
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document.write( "Now, there are 2 major configurations of favorable placings, a) and b)\r\n" );
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document.write( "  a)                            b) \r\n" );
document.write( "                     A  B                           B  A\r\n" );
document.write( "   1  2  3  4  5  6  7  8         1  2  3  4  5  6  7  8\r\n" );
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document.write( "where April and Bobby occupy chairs ## 7 and 8.\r\n" );
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document.write( "For configuration a), we have   = 6*7 = 42 possible placings of two other persons.\r\n" );
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document.write( "For configuration b), we have   = 6*7 = 42 possible placings two other persons  (the same number as in a).\r\n" );
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document.write( "So the number of favorable placings is  42+42 = 84.\r\n" );
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document.write( "Now the probability under the question is  P =  = 0.05.    ANSWER\r\n" );
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