document.write( "Question 1174769: Homer and Mike were replacing the boards on​ Mike's old deck. Mike can do the job alone in 1 hour less time than Homer. They worked together for 5 hours until Homer had to go home. Mike finished the job working by himself in an additional 2 hours. How long would it have taken Homer to fix the deck​ himself? \n" ); document.write( "
Algebra.Com's Answer #800254 by VFBundy(438)\"\" \"About 
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Homer's rate of work = \"1%2Fx\" of the job per hour
\n" ); document.write( "Mike's rate of work = \"1%2F%28x-1%29\" of the job per hour
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\n" ); document.write( "Rate of work working together = \"1%2Fx\" + \"1%2F%28x-1%29\" of the job per hour
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\n" ); document.write( "Simplify:
\n" ); document.write( "
\n" ); document.write( "\"%28x-1%29%2F%28x%28x-1%29%29\" + \"x%2F%28x%28x-1%29%29\"
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\n" ); document.write( "\"%28x-1%2Bx%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "\"%282x-1%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "Rate of work working together = \"%282x-1%29%2F%28x%28x-1%29%29\" of the job per hour
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\n" ); document.write( "After working five hours together, calculate the amount of the job that was completed:
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\n" ); document.write( "\"5+%2A+%28%282x-1%29%2F%28x%28x-1%29%29%29\"
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\n" ); document.write( "\"%2810x+-+5%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "Therefore, the amount of the job that is left to be completed is:
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\n" ); document.write( "\"1-+%2810x+-+5%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "\"%28x%28x-1%29%29%2F%28x%28x-1%29%29+-+%2810x+-+5%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "\"%28x%5E2-x%29%2F%28x%28x-1%29%29+-+%2810x+-+5%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "\"%28x%5E2+-+x+-+%2810x+-+5%29%29%2F%28x%28x-1%29%29\"
\n" ); document.write( "
\n" ); document.write( "\"%28x%5E2+-+x+-+10x+%2B+5%29%2F%28x%28x-1%29%29\"
\n" ); document.write( "
\n" ); document.write( "\"%28x%5E2+-+11x+%2B+5%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "Mike finishes the job in two hours. This means Mike's rate of work per hour is:
\n" ); document.write( "
\n" ); document.write( "\"1%2F2\"* \"%28x%5E2+-+11x+%2B+5%29%2F%28x%28x-1%29%29\"
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\n" ); document.write( "\"%28x%5E2+-+11x+%2B+5%29%2F%282x%28x-1%29%29\"
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\n" ); document.write( "So, Mike's rate of work is \"%28x%5E2+-+11x+%2B+5%29%2F%282x%28x-1%29%29\" of the job per hour.
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\n" ); document.write( "From earlier, we know that Mike's rate of work is also \"1%2F%28x-1%29\" of the job per hour. Therefore:
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\n" ); document.write( "\"%28x%5E2+-+11x+%2B+5%29%2F%282x%28x-1%29%29\" = \"1%2F%28x-1%29\"
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\n" ); document.write( "Solve for x.
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\n" ); document.write( "Cross-multiply:
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\n" ); document.write( "\"%28x-1%29%28x%5E2+-+11x+%2B+5%29\" = \"2x%28x-1%29\"
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\n" ); document.write( "\"%28x%5E2+-+11x+%2B+5%29\" = \"2x\"
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\n" ); document.write( "\"x%5E2+-+13x+%2B+5\" = \"0\"
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\n" ); document.write( "Use the quadratic formula to solve for x:
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\n" ); document.write( "x = \"%2813-sqrt%28149%29%29%2F2\" = 0.40
\n" ); document.write( "x = \"%2813%2Bsqrt%28149%29%29%2F2\" = 12.60
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\n" ); document.write( "There are two solutions. Because Mike's rate of work is \"1%2F%28x-1%29\" of the job per hour, the first solution, x = 0.40, would make Mike's rate of work \"1%2F%28-0.60%29\". Since this is a negative rate of work, this is impossible.
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\n" ); document.write( "Therefore, we are left with x = 12.60
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\n" ); document.write( "We are looking how long it would have taken Homer to fix the deck working alone. Homer's rate of work is \"1%2Fx\" of the job per hour. Plugging in x = 12.60, this means Homer's rate of work is \"1%2F12.60\" of the job per hour. This means it would have taken Homer 12.60 hours to fix the deck working alone.
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