Algebra.Com's Answer #648793 by ikleyn(52786)![\"\"](\"/images/stars/stars-13.gif\")  
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document.write( "3 men and 18 children together take 2 days to complete a piece of work.
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document.write( "How many days will 18 children alone take to complete the piece of work,
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document.write( "if 6 men alone can complete the piece of work in 3 days?
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document.write( "Let m be the man's rate of work, in terms of  , and\r\n" );
document.write( "let c be the child's rate of work, in the same terms.\r\n" );
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document.write( "Then from the condition you have this system of equations\r\n" );
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document.write( "3m + 18c =  , (1)\r\n" );
document.write( "6m =  . (2)\r\n" );
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document.write( "From (2), m =  =  .\r\n" );
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document.write( "Substitute it into (1). You will get\r\n" );
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document.write( " + 18c = --->  + 18c = ---> 18c =  =  = .\r\n" );
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document.write( "Hence, c =  =  .\r\n" );
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document.write( "This is rate of work of one child.\r\n" );
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document.write( "So, 18 children will complete of the job in one day, and\r\n" );
document.write( "it will take 3 days for them to complete the job.\r\n" );
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document.write( "Answer. 3 days.\r\n" );
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