Two pipes P and Q can fill a tank in 20hrs and 25hrs respectively while a third pipe R can empty the tank in 30hrs. If all the pipes are opened together for 10hrs and then pipe R is closed then in what time the tank can be filled.

A

$$\dfrac{400}{23} \ \text{hrs}$$

B

$$\dfrac{400}{27} \ \text{hrs}$$

C

$$\dfrac{200}{23} \ \text{hrs}$$

D

$$\dfrac{200}{27} \ \text{hrs}$$