- A3 p.m.
- B4 p.m.
- C2 p.m.
- D5 p.m.
Step-by-Step Solution
In 24ths: A 3/h, B −2/h. 6–8 a.m.: 6. 8–11 a.m.: net 1/h → 9. Then A fills the last 15 at 3/h in 5 h → 4 p.m. (2 p.m. is A alone.)
Answer: B) 4 p.m.
Pipe A fills a tank in 8 hours and pipe B empties it in 12 hours. With the tank empty, A is opened at 6 a.m. Someone opens B by mistake at 8 a.m. and closes it again at 11 a.m. At what time is the tank full?
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