A pipe can fill the tank in = 10 hours ∴ In 1 hour pipe can fill = 1/10 Tank is actually filled in = 12 hours ∴ In 1 hour tank actually fills = 1/12 ∴ In 1 hour the leak empties, ⇒
1
10
−
1
12
⇒6−
5
60
⇒ 1/60 ∴ The leak can empty the whole tank in = 60 hours