<PRE><B>Question 768464</B>
Kayla&#39;s copy store recived an order for 5,616 copies. The store has 3 printers. If Kayla only uses one printer at a time, the first printer would complete the job in 15 hours and 36 minutes, the second in 7 hours and 12 minutes, and the third in 11 hours and 42 minutes. How long would it take to process if all three printers were used at the same time?
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15 hrs and 36 min = 15.6 hrs
7 hrs and 12 min = 7.2 hrs
11 hrs ad 42 min = 11.7 hrs
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1st printer rate = 1/15.6 job/hr
2nd printer rate = 1/7.2 job/hr
3rd printer rate = 1/11.7 job/hr
together rate = 1/x job/hr
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Equation:
1/15.6 + 1/7.2 +1/11.7 = 1/x
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7.2*11.7x + 15.6*11.7x + 15.6*7.2x = 15.6*7.2*11.7
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79.2x + 182.52x + 112.32x = 1314.144
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374.04x = 1314.144
x = 3.5134 hrs = 3hrs 30.8 minutes (time to do the job together)
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Cheers,
Stan H.
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