document.write( "Question 352388: 10 people line up for a photo, including you and your friend. How many line arrangements are there if the photographer insists on keeping 3 people in between you and your friend? \n" ); document.write( "
Algebra.Com's Answer #252130 by nyc_function(2741)![]() ![]() You can put this solution on YOUR website! There are 10 people: A(you), B(your friend) and 8 others.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "You and your friend are spaced like this:\r \n" ); document.write( "\n" ); document.write( "A____B or B____A = two ways\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Select 3 of the Others and arrange them in the spaces. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "There are: 8P3 = 8!/5! = 336 ways.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now we have 6 \"people\" to arrange: AxyzB and 5 others.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "There are: 6! = 720 ways.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Therefore, there are: 2 * 336 * 720 = 483,840 line arrangements. \n" ); document.write( " \n" ); document.write( " |