Pipes A and B together can fill a tank in 10 hours. Pipes B and C together can fill the same tank in 12 hours. Pipes A and C together can fill the same tank in 15 hours. In how many hours can pipe B alone fill the same tank?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 120/7 hours.
Total work (LCM of 10, 12, and 15) = 60 units
Efficiency of A and B = 60/10 = 6
Efficiency of B and C = 60/12 = 5
Efficiency of C and A = 60/15 = 4
Total Efficiency of (A + B + C) = 15/2 = 7.5
Efficiency of B = Efficiency of (A + B + C) - Efficiency of (A + C) = 7.5 - 4 = 3.5
Hence, time taken by B = 60/3.5 = 120/7