Two pipes A and 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

A

$$ 8\frac{2}{11}$$

B

$$9\frac{2}{11}$$

C

$$7\frac{2}{11}$$

D

$$10\frac{2}{11}$$