Question

Two pipes can fill the cistern in 10hr and 12 hr respectively, while the third empty it in 20hr. If all pipes are opened simultaneously, then the cistern will be filled in

Answer 1

Answer:

Step-by-step explanation:

       Pipe A               Pipe B                  Pipe C (Negative work)

       10 hrs               12 hrs                    -20hrs

Let's assume total work is 60 units (Which is also LCM of 10,12 & 20)

Then the Work pipes would do will be=

Pipe A= 60/10 = 6 units

Pipe B= 60/12 = 5 units

Pipe C= 60/20= -3 units (Negative value because it is emptying the tank)

Therefore, total capacity of A+B+C = 6+5-3 = 8 units

Time taken to fill the cistern= 60/8 = 7.5 hrs or 7 hrs and 30 minutes.