A 800 ml bottle can be filled in 30 seconds using Pipe A. If a second pipe is added with the first, the total time taken to fill the bottle decreases to 10 seconds.
To fill the bottle in 10 seconds, the rate at which water flows in using both the pipes is 80 ml/s. The rate at which water is supplied by pipe A is `800/30` . This gives the rate at which water is supplied by the second pipe as `80 - 800/30 = 160/3 ` ml/s
The second pipe fills the bottle at `160/3` ml per second.