document.write( "Question 1120492: together it takes dawn and deb 2 hr 55 min to sort recyclables. alone dawn would require 2 more hours then deb how long would it take deb to do the the job alone \n" ); document.write( "
Algebra.Com's Answer #736154 by ankor@dixie-net.com(22740)\"\" \"About 
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together it takes dawn and deb 2 hr 55 min to sort recyclables.
\n" ); document.write( " alone dawn would require 2 more hours then deb
\n" ); document.write( "how long would it take deb to do the the job alone:
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\n" ); document.write( "Change times to minutes
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\n" ); document.write( "let d = time required by Dawn alone
\n" ); document.write( "then
\n" ); document.write( "(d-120) = time required by Deb
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\n" ); document.write( "Change 2 hrs 55 min: to 175 min
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\n" ); document.write( "Let the completed job = 1, each will do a fraction of the job, the fractions add up to 1
\n" ); document.write( "\"175%2Fd\" + \"175%2F%28%28d-120%29%29\" = 1
\n" ); document.write( "multiply equation by d(d-120), cancel the denominators
\n" ); document.write( "175(d-120) + 175d = d(d-12)
\n" ); document.write( "175d - 21000 + 175d = d^2 - 120d
\n" ); document.write( "350d - 21000 = d^2 - 120d
\n" ); document.write( "form a quadratic equation on the right
\n" ); document.write( "0 = d^2 - 120d - 350d + 21000
\n" ); document.write( "d^2 - 470d + 21000 = 0
\n" ); document.write( "Solve with the quadratic formula a=1; b=-470; c=21000
\n" ); document.write( "Two solutions
\n" ); document.write( "d=50
\n" ); document.write( "d=420 min, the only one that makes sense
\n" ); document.write( "420/60 = 7 hrs Dawn working alone
\n" ); document.write( "then
\n" ); document.write( "7 - 2 = 5 hrs Deb working alone\r
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