document.write( "Question 937770: four flags of different colours are given.How many signals can be given by these flags \n" ); document.write( "
Algebra.Com's Answer #571878 by Edwin McCravy(20055)\"\" \"About 
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document.write( "We can choose the flag to put on the top position 4 ways.\r\n" );
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document.write( "For each of those 4 ways to put a flag on the top position,\r\n" );
document.write( "there are 3 flags remaining to choose to put just underneath \r\n" );
document.write( "it.\r\n" );
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document.write( "That's 4×3 or 12 ways to place two flags in the top two \r\n" );
document.write( "positions.\r\n" );
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document.write( "For each of those 4×3 or 12 ways to choose flags for\r\n" );
document.write( "the top two positions, there are 2 flags remaining to choose\r\n" );
document.write( "to put next to the bottom position.\r\n" );
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document.write( "That's 4×3×2 or 12×2 or 24 ways to choose flags\r\n" );
document.write( "for the top 3 positions.\r\n" );
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document.write( "Now there is only one flag left and only one position at the\r\n" );
document.write( "bottom to place it in, so we just multiply by 1, and we still\r\n" );
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document.write( "4×3×2×1 = 4! = 24 ways to arrange the flags in different orders. \r\n" );
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document.write( "This is also called \"the number of permutations of 4 things \r\n" );
document.write( "taken 4 at a time.\"\r\n" );
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document.write( "Edwin
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