- A9 h
- B12 h
- C10.5 h
- D7.5 h
Step-by-Step Solution
In 3 h: . Then per hour, so emptying takes h. Total 10.5 h. (7.5 h is only the emptying stage.)
Answer: C) 10.5 h
Pipes A and B fill a tank in 8 and 12 hours, and pipe C empties it in 6 hours. A and B are opened together on the empty tank; after 3 hours A is closed and C is opened. How long after the start will the tank be empty again?
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