A pump can fill a tank in 2 hours. Due to a leak in the tank it takes 2
hours to fill the tank. The leak can empty the full tank in
A pipe can fill a cistern in: 2 hours
Let a leak empty the cistern in: X hours
Due to the leak time taken to fill the cistern : 2
= 
hours
Part of the cistern filled by pipe in one hour: 
Part of the cistern emptied by leak in one hour: 
= 
= 
= 
X = 14 hours
Therefore the leak will empty the cistern in 14 hours.
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