Inject water into tube A for 3 hours: (1/9)×3=( 1/3),

A and B pump water together for 5 hours: ((1/9)+(110)) × 5 = (19/18).

The pipes A and B are submerged for 5 hours, which is more than that of the pipe A alone for 3 hours: (19/18)-(1/3) = (13/18),

∴ efficiency of drainage pipe: (1318) ÷ (5-3) = (13/36)

∴ Raw water in the pond: (13/36) × 3-(1/3) = (3/4). Or (13/36) × 5-(19/18).

Therefore, there was water in the pool: 1.200×(3/4)= 900 liters.

The water pipe A can fill the pool within 9 hours, so the water pipe A can be injected 1200 ÷ 9 = 400/3 (liters) per hour.

The water pipe B can fill the pool within 10 hour, so the water pipe B can inject1200 ÷10 =120 liters per hour.

A drain pipe can discharge x liters of water per hour, and the same amount of water can be discharged at the same time.

(X-400/3)* 3 =(X-400/3- 120)* 5

X = 1300。

Raw water * * * (1300-400)*3=900 liters.