Tap A alone can fill the tank in 30 hours while tap B alone can fill the tank in 12 hours. Tap C empties the filled tank. When all three taps are opened then the tank gets emptied in 20 hours. In what time the tank gets emptied when Tap C is opened after 1/4th of the tank is filled by tap A and tap B?
1
1 hour and 40 minutes
2
1 hour and 30 minutes
3
1 hour and 15 minutes
4
1 hour and 20 minutes
5
1 hour and 50 minutes