Q.Two pipes 'A' and 'B' can fill an empty tank in 8 hours and 12 hours respectively, while pipe 'C' can empty a full tank in 6 hours. When the tank is empty, pipes 'A' and 'B' are opened and after 2 hours, pipe 'C' is also opened. In how many hours will the tank be completely filled?
Correct answer: 16