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Question 608940: Help plz!
When the tank is full with the faucet is closed, and the drain is open, the tank will drain in 10 hrs. When the tank is empty with the faucet is open, and the drain is open, an empty tank will fill in 5 hours. How long will it take to fill the empty tank if the tap is turned on and the drain is closed?
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! When the tank is full with the faucet is closed, and the drain is open, the tank will drain in 10 hrs. When the tank is empty with the faucet is open, and the drain is open, an empty tank will fill in 5 hours. How long will it take to fill the empty tank if the tap is turned on and the drain is closed?
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Drain will empty tank by itself in 10 hours
Its work rate=1/10
Faucet will fill tank by itself in x hours
Its work rate=1/x
..
faucet open, drain open, empty tank will fill in 5 hours.
5(1/x)-5(1/10)=1
5/x)-5/10)=1
5/x)-1/2)=1
5/x=3/2
3x=10
x=10/3
Ans:
It will take 10/3 hrs to fill empty tank if the tap is turned on and the drain is closed.
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