Question

There are three pipes A, B, C in a tank. If all the three pipes are open together the tank will be filled in 15 minutes. A and C are open together the tank will be fill in 20 minutes if B alone is open the tank will be filled in how many minutes ?

• A. 45 minutes
• B. 30 minutes
• C. 1 hour 30 minutes
• D. 1 hour

Answer 1

Answer:

D. 1 hour

Total capacity of tank = LCM[15, 20] = 60 Efficiency of A , B , C= 60/15 = 4 Efficiency of A and C = 60/20 = 3 Efficiency of B = 4 - 3 = 1 Time taken by B to fill the tank = 60/1 = 60 minute = 1 hour