document.write( "Question 730582: A farmer has a combined total of 30 pigs and ducks and there is a combined total of 100 legs. \r
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Algebra.Com's Answer #446783 by Edwin McCravy(20062) $\"\"$ $\"About$

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A farmer has a combined total of 30 pigs and ducks and there is a combined total of 100 legs. How many of each animal is there?
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document.write( "There are two ways to do it -- with algebra and without algebra.  \r\n" );
document.write( "I'll do both.  \r\n" );
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document.write( "1.  WITHOUT ALGEBRA:\r\n" );
document.write( "There are 100 legs, so there are 50 pairs of legs. \r\n" );
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document.write( "Ducks have one pair of legs and pigs have two pairs of leg.\r\n" );
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document.write( "If all 30 were ducks, there would only be 30 pairs of legs.\r\n" );
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document.write( "But there are 50 pairs of legs, so the extra 20 pairs of legs must\r\n" );
document.write( "belong to the pigs.  \r\n" );
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document.write( "So there are 20 pigs and since there are 30 animals there are 10 ducks.\r\n" );
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document.write( "2.  WITH ALGEBRA:\r\n" );
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document.write( " d +  p = 30\r\n" );
document.write( "2d + 4p = 100\r\n" );
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document.write( "Solve that system by substitution or elimination and get d=10, p=20\r\n" );
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document.write( "Edwin

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