Pipe A can fill a tank in 5 hours. Pipe B can fill it in 2 hours less time than it takes pipe C, a draining pipe, to empty the tank. With all 3 pipes open, it takes 3 hours to fill the tank. How long will it take pipe C to empty it?

Time taken by pipe C to empty the tank = 5 hours.

Step-by-step explanation:

Pipe A can fill a tank in 5 hours.

Let time taken by Pipe C = x ( hours)

Time taken by Pipe B = x-2 ( hours)

Now, with all 3 pipes open, it takes 3 hours to fill the tank, it can be represented as

Time cannot be negative,

So, x=5

Thus, Time taken by pipe C to empty the tank = 5 hours.