- A19.5 h
- B15 h
- C13.5 h
- D10.5 h
Step-by-Step Solution
Fill: 6 h. Drain half: 4.5 h. Refill half at : 9 h. Total 19.5 h. (10.5 h forgets the drain is still running.)
Answer: A) 19.5 h
A pipe fills a tank in 6 hours. When the tank is full, the pipe is shut and a drain that empties it in 9 hours is opened. When the tank is half empty, the pipe is opened again with the drain still running. How long, from the very start, until the tank is full again?
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