Two pipes A and B can fill a tank in 15 hours and 18 hours, respectively. Both pipes are opened simultaneously to fill the tank. In how many hours will the empty tank be filled?
1
\(8 \frac{2}{11}\)
2
\(7 \frac{2}{11}\)
3
\(9 \frac{2}{11}\)
4
\(10 \frac{2}{11}\)