document.write( "Question 239061: There are entrees 17 available at a restaurant. From these, Archie is to choose 4 for his party. How many groups of 4 entrees can he choose, assuming that the order of the entrees chosen does not matter? \n" ); document.write( "
Algebra.Com's Answer #175580 by Theo(13342)![]() ![]() You can put this solution on YOUR website! 17! / (4!*13!) = 17*16*15*14*13!/(4!*13!) = 17*16*15*14/(4*3*2) = 17*2*5*14 = 2380\r \n" ); document.write( "\n" ); document.write( "smaller number lets you see it better.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "assume 2 out of 5\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "5!/2!3! = 5*4/2 = 10\r \n" ); document.write( "\n" ); document.write( "let abcde be the possible choice of entrees.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "possible sets of 4 combinations (order not important) are:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "ab \n" ); document.write( "ac \n" ); document.write( "ad \n" ); document.write( "ae \n" ); document.write( "bc \n" ); document.write( "bd \n" ); document.write( "be \n" ); document.write( "cd \n" ); document.write( "ce \n" ); document.write( "de\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your problem is the same with bigger numbers.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the formula for number of combinations is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "n! / (x!*(n-x)!)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "where\r \n" ); document.write( "\n" ); document.write( "n is the total number of possible entrees \n" ); document.write( "x is the number of entrees in each set.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your formula becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "17! / ((4!*(17-4)!) which becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "17! / (4!*13!) as shown above.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |