document.write( "Question 689322: it takes Tom 9 hours working alone to stucco the walls of his home. It takes Todd 12 hours to do the same amount of work. Tom worked on a house for 4 hours by himself and then Todd joined him to finish the job. How many more hours did it take to complete the job? \n" ); document.write( "

Algebra.Com's Answer #425961 by Edwin McCravy(20056) $\"\"$ $\"About$

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it takes Tom 9 hours working alone to stucco the walls of his home. It takes Todd 12 hours to do the same amount of work. Tom worked on a house for 4 hours by himself and then Todd joined him to finish the job. How many more hours did it take to complete the job?\r
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document.write( "We are given Tom's stuccoing rate as 1 job per 9 hours, or\r\n" );
document.write( " or \r\n" );
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document.write( "We are given Todd's stuccoing rate as 1 job per 12 hours, or\r\n" );
document.write( " or \r\n" );
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document.write( "Let X = the number of hours it will take to finish the job after Todd\r\n" );
document.write( "joins in.\r\n" );
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document.write( "So Todd will have worked only X hours whereas Tom will have worked 4 hours\r\n" );
document.write( "before Todd joined him, so the X hours are added to the 4 hours Tom has \r\n" );
document.write( "already worked, or Tom has worked a total of 4+X hours.\r\n" );
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document.write( "The fraction of the job that Tom did equals his rate times his time, or\r\n" );
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document.write( " or \r\n" );
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document.write( "The fraction of the job that Todd did equals his rate times his time, or\r\n" );
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document.write( " or  \r\n" );
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document.write( "The equation comes from:\r\n" );
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document.write( "      .\r\n" );
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document.write( "              \r\n" );
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document.write( "Solve that by multiplying through by the LCD of 36.\r\n" );
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document.write( "Answer:  hours or  hours or about 2 hours 52 minutes \r\n" );
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document.write( "Edwin

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