Two inlet pipes A and B and an outlet pipe C together can fill a tank in 15 minutes and pipes A and C together can empty that tank completely in 30 minutes. If time taken by pipes B and C together to fill that tank is 1 hour, then what is the time taken by pipes A and B together to fill that tank?
Two inlet pipes A and B and an outlet pipe C together can fill a tank in 15 minutes and pipes A and C together can empty that tank completely in 30 minutes. If time taken by pipes B and C together to fill that tank is 1 hour, then what is the time taken by pipes A and B together to fill that tank? Correct Answer 12 minutes
Let capacity of tank = LCM of (15, 30 and 60) = 60 units
The efficiency of A + B + C = 4 units -----(1)
The efficiency of A + C = 2 units ----(2)
The efficiency of B + C = 1 units ----(3)
Putting (3) in (1), we get
A = 3 units
Hence, from (2) C = -1 units and from (3) B = 2 units
Hence, combined efficiency of A and B = 5 units
∴ Time taken = 60/5 = 12 minutes
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Feb 20, 2025