<PRE><B>Question 793474</B>
it takes an hp laserjet 1300 10 minutes longer to complete a 600-page print job by itself than it takes an HP Laserjet 2420 to complete the same job by itself. Together the two printers can complete the job in 12 minutes. How long does it take each printer to complete the job alone? what is the speed of each printer?
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HP 2420 DATA:
time = x min/job ; rate = (1/x) job/min
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HP 1300 DATA:
time = (x+10) min/job ; rate = 1/(x+10) = job/min
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Together DATA:
time = 12 min/job ; rate = 1/12 job/min
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Equation:
rate + rate = together rate
1/x + 1/(x+10) = 1/12
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12(x+10) + 12x = x(x+10)
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12x + 120 + 12x = x^2 + 10x
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x^2 + -14x - 120 = 0
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x = 20 min (HP 2420 time to do the job)
x + 10 = 30 min (HP 1300 time to do the job)
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Cheers,
Stan H.</PRE>