- A9 h
- B10 h
- C9 h 40 min
- D9 h 20 min
Step-by-Step Solution
In 18ths: open hour , shut hour 3; each 2-hour cycle gives 4. After 8 h: 16; hour 9 (open): 17; hour 10 (shut) needs 1 of 3 → 20 min. Total 9 h 20 min.
Answer: D) 9 h 20 min
An inlet fills a tank in 6 hours and an outlet empties it in 9 hours. The inlet stays open, while the outlet is open and shut in alternate hours, starting open in the first hour. How long does the empty tank take to fill?
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