Pipe A and B can fill a tank in 10 hours and 20 hours respectively, if an outlet pipe C is left open which can empty the tank in 40 hours then in how much time will the tank be filled if they are opened together?
Pipe A and B can fill a tank in 10 hours and 20 hours respectively, if an outlet pipe C is left open which can empty the tank in 40 hours then in how much time will the tank be filled if they are opened together?
A10 hours
B40/7 hours
C8 hours
D7 hours
All DiscussionsClick here to write answer
correct answer is: option c [8 hours]
Explanation: Let the capacity of the tank be LCM(10, 20, 40) = 40 units.
Pipe A can fill 40/10 = 4 units/hour.
Pipe B can fill 40/20 = 2 units/hour.
Outlet pipe C can empty 40/40 = 1 unit/hour.
When all three pipes are opened together, the net filling rate is 4 + 2 - 1 = 5 units/hour.
Therefore, the time taken to fill the tank is 40/5 = 8 hours.
Post your answers here:
Post
