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A tank can be filled by one pump in 3.2 hours and by another pump in 80 minutes. A third pump can drain the tank in 2 hours and 20 minutes. If all 3 pumps go into operation, how long will it take to fill the tank?

 Jan 20, 2020
 #1
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1 tank / 3.2 hr   = rate 1

1 tank / 1.33 hr = rate 2

- 1tank/2.33 hr  = rate 3

 

 

1 / (1/3.2 + 1/1.33 - 1/2.33) =  1.574 hr for 1 tank to be filled with all three running

 Jan 20, 2020

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