Question

pipe a can fill A tank in 10 hours and pipe B can empty in 15 hour in how many hour will the tank be filled if both the pipes are opened

Answer 1

Answer:

30 hours

Step-by-step explanation:

Pipe A can fill the tank in 10 hours

=> Pipe A can fill 1/10 of the tank in 1 hour

Pipe B can empty the tank in 15 hours

=> Pipe B can empty 1/15 of the tank in 1 hour

If both pipes A and B are kept on for 1 hour,

A will be filling 1/10 of the tank AND

B will be filling -1/15 of the tank ("filling" in the negative sense is "emptying")

the net effect will be 1/10 - 1/15 = 3/30 - 2/30 = 1/30

=> The net effect will be that in 1 hour 1/30 of the tank will be filled.

=> If 1/30 of the tank is filled in 1 hour, the full tank will be filled in 30 hours.

Answer: It will take 30 hours for the tank to fill when both pipes A and B are simultaneously opened.