<PRE><B>Question 489454</B>
1 pipe can fill a large tank in 5 hours and a smaller pipe can fill the same tank in 3 hours. How long will it take both pipes to fill the tank if they are turned on at the same time? 
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1st pipe rate = 1/5 job/hr
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Smaller pipe rate = 1/3 job/hr
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Together pipe rate = 1/x job/hr
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Equation:
rate + rate = together rate
1/5 + 1/3 = 1/x
5x + 3x = 15
8x = 15
x = 15/8 hrs = 1 hr 52.5 minutes) (time to do the job together)
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Cheers,
Stan H.
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