SOLUTION: Filling a tank. A water tank has an inlet pipe and a drain pipe. A full tank can be emptied in 30 minutes if the drain is opened and an empty tank can be filled in 45 minutes with
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-> SOLUTION: Filling a tank. A water tank has an inlet pipe and a drain pipe. A full tank can be emptied in 30 minutes if the drain is opened and an empty tank can be filled in 45 minutes with
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Question 285929: Filling a tank. A water tank has an inlet pipe and a drain pipe. A full tank can be emptied in 30 minutes if the drain is opened and an empty tank can be filled in 45 minutes with the inlet pipe opened. If both pipes are accidentally opened when the tank is full, then how long will it take to empty the tank?
You can put this solution on YOUR website! Let x=amount of time for pool to empty if both pipes are open
Then with both pipes open the pool empties at the rate of 1/x pool per min
Drain pipe empties at the rate of 1/30 pool per min
Inlet pipe fills at the rate of 1/45 pool per min
With both pipes open, the pool empties at the rate of:
1/30-1/45 pool per min, so:
1/30 - 1/45=1/x multiply each term by 90x
3x-2x=90
x=90 min----- time for pool to empty if both pipes are open
CK
with inlet pipe open, in 90 min we get 2 pools of water
with drain pipe open, in 90 min we drain 3 pools of water
3 pools - 2 pools= 1 pool of water drained
Hope this helps---ptaylor
You can put this solution on YOUR website! x/45-x/30=1
We start with the tank full and are filling it and draining it.
x=-90
means it takes 90 minutes to drain it
in 90 minutes
We start with a full tank. It is filled 2 more times and drained 3 times
