document.write( "Question 405292: office has an old copying machine and a new one. together it takes both machines 4 hours to copy all financial reports. alone it takes the old copier 15 hours longer than the new one to make all copies . how long will it take the new copying machine to make all the copies \n" ); document.write( "
Algebra.Com's Answer #286290 by stanbon(75887)\"\" \"About 
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office has an old copying machine and a new one.
\n" ); document.write( "together it takes both machines 4 hours to copy all financial reports.
\n" ); document.write( "alone it takes the old copier 15 hours longer than the new one to make all copies .
\n" ); document.write( "how long will it take the new copying machine to make all the copies
\n" ); document.write( "-------------------------
\n" ); document.write( "New copier DATA:
\n" ); document.write( "time = x hrs/job ; rate = 1/x job/hr
\n" ); document.write( "-----
\n" ); document.write( "Old copier DATA:
\n" ); document.write( "time = (x+15) hrs/job ; rate = 1/(x+15)job/hr
\n" ); document.write( "----
\n" ); document.write( "Together DATA:
\n" ); document.write( "time = 4 hrs/job ; rate = 1/4 job/hr
\n" ); document.write( "==========================================
\n" ); document.write( "Equation:
\n" ); document.write( "rate + rate = together rate
\n" ); document.write( "1/x + 1/(x+15) = 1/4
\n" ); document.write( "Multiply thru by 4x(x+15) to get:
\n" ); document.write( "4(x+15) + 4x = x(x+15)
\n" ); document.write( "---
\n" ); document.write( "4x + 60 + 4x = x^2+15x
\n" ); document.write( "---
\n" ); document.write( "x^2 + 7x - 60 = 0
\n" ); document.write( "x^2+12x-5x-60 = 0
\n" ); document.write( "x(x+12)-5(x+12) = 0
\n" ); document.write( "(x+12)(x-5) = 0
\n" ); document.write( "Positive solution:
\n" ); document.write( "x = 5 hrs (time for the new machine)
\n" ); document.write( "x+15 = 20 hrs (time for the old machine)
\n" ); document.write( "==================================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "
\n" );