It is given that the inlet pipe can fill a tank in 6 hours but because of a leak it took 40 more minutes to fill the tank.
Now, here we can say,
Work done by the inlet in 40 minutes = Work done by the leak in 6 hours
Work done by the inlet in 40/60
hour = Work done by the leak in 6 hours
Work done by the inlet in 2/3
hour = Work done by the leak in 6 hours
Since, the inlet pipe fill the tank in 6 hours, so to get 6 in LHS we will multiply both
sides by 9
Work done by the inlet in 2/3 × 9 hour = Work done by the leak in 6 × 9 hours
Work done by the inlet in 6 hours = Work done by the leak in 54 hours
Hence, the leak will take 54 hours to empty the tank when inlet pipe is not operating.
E is the answer
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