document.write( "Question 479212: A project can be done by 8 girls in 5 days. 5 boys can do the same project in 6 days. How long will it take for 3 boys and 6 girls to do the job? \n" ); document.write( "

Algebra.Com's Answer #328400 by Edwin McCravy(20056) $\"\"$ $\"About$

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A project can be done by 8 girls in 5 days. 5 boys can do the same project in 6 days. How long will it take for 3 boys and 6 girls to do the job?
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document.write( "8 girls can do it in 5 days, so 1 girl can do it in 40 days.\r\n" );
document.write( "So each girl's rate is 1 job per 40 days or  job/day\r\n" );
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document.write( "5 boys can do it in 6 days, so 1 boy can do it in 30 days.\r\n" );
document.write( "So each boy's rate is 1 job per 30 days, or  job/day.\r\n" );
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document.write( "3 boy's combined rate is  or  jobs/day\r\n" );
document.write( "6 girl's combined rate is  or  jobs/day.\r\n" );
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document.write( "Let x be the number of days for 3 boys and 6 girls to do the job.\r\n" );
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document.write( "Then in those x days, the boys do x of the job and the girls \r\n" );
document.write( "do x of the job.  That must add to 1 job so the equation is\r\n" );
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document.write( "                x + x = 1\r\n" );
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document.write( "Multiply through by 20\r\n" );
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document.write( "                 2x + 3x = 20\r\n" );
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document.write( "                      5x = 20\r\n" );
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document.write( "                       x = 4 days\r\n" );
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document.write( "Edwin

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