Question

Tap A takes 6 minutes to fill a tank and Tap B
takes 9 minutes to fill the same tank. Pipe C can
empty the tank in 15 minutes. How long will it
take to fill up the tank if the pipe is in use when
both taps are turned on?​

Answer 1

Answer:

All together in 1 minute they fill the tank = 1/6+1/9 -1/15 = {15 +10 -6}/90 = 19/90 of tank.

Step-by-step explanation:

Each minute that passes, Tap A fills 1/6 of the tank and Tap B fills 1/9 of the tank, while Pipe C is draining 1/15 of the tank per minute.

Thus, 1/6 + 1/9 - 1/15 = 19/90 of the tank fills per minute, and so it will take 90/19, or approximately 4:44 to fill the tank.