Two pipes A and B can fill an empty tank in 6 hours and 12 hours respectively, while the third pipe C can empty a full tank in 15 hours. If all the three pipes are opened at the same time, in how many hours will the empty tank be filled?
1
\(\dfrac{60}{13}\)
2
\(\dfrac{60}{11}\)
3
\(\dfrac{60}{19}\)
4
\(\dfrac{20}{3}\)