<PRE><B>Question 186736</B>
    The HP Laser Jet 9000 works twice as fast as the Laser Jet 2300. If the machines work together, a university can produce all its staff manuals in 15hr. Find the time it would take each machine, working alone, to complete the same job?
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Let x = speed of Laser Jet 2300
then 
2x = speed of Laser Jet 9000
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15(x + 2x) = 1
15x + 30x = 1
45x = 1
x = 1/45 
the above says, completes a job in 45 hours (speed of Laser Jet 2300)
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Laser Jet 9000:
2x = 2(1/45) = 2/45 = 1/22.5
the above says, completes a job in 22.5 hours (speed of Laser Jet 9000)
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