Pipe A can fill the tank in 30 hours and pipe B can fill the tank in 15 hours whereas pipe C can empty the tank 10 hours. Pipe A starts at 6:00 am pipe B starts at 7:00 am and from 8:00 am all the pipes run alternatively find in how many hours the tank will be filled or empty completely?
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30 hours to fill
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25 hours to fill
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30 hours to empty
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25 hours to empty
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cannot be determined
E
Correct answer
Explanation
The phrase all pipes run alternatively is ambiguous - it could mean hourly rotation, minute-by-minute switching, or some other pattern. Without clarifying what alternatively means in this context, it is impossible to determine whether and when the tank fills or empties. Option E correctly identifies this indeterminacy.