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czsassyone
Sep 16, 2012, 09:44 AM
At the Seattle sewage treatment plant, one pipe can fill a settling tank in 6 hrs while another can fill the same tank in 9 hrs. A drain can empty a full tank in 4 hrs.

If both pipes and the drain are opened at midnight, how many hrs will it take to fill the tank?

If both pipes are opened at midnight, and the drain is opened at 1am at what time is the tank filled?

If the pipes are opened at midnight and the drain is opened at 1am but closed at 2am, at what time is the tank filled?

Unknown008
Sep 16, 2012, 09:45 AM
What is your attempt?