Question
Pipe A can fill a tank in 10 hours, whereas pipe B can
empty the same tank in 12 hours. If the two pipes are operated alternately for one hour each, starting with pipe A, how much time will it take to completely fill the tank?Solution
Let the total capacity of the tank be 60 units
Efficiency of pipe ‘A’ = 60/10 = 6 units/hour
Efficiency of pipe ‘B’ = 60/12 = 5 units/hour
Amount of tank filled in 2 hours = 6 – 5 = 1 units
Therefore, amount of tank filled in (2 × 54) hours = 54 units
Therefore, remaining six unit will be filled in 6/6 = 1 hour
Total time taken = 2 × 54 + 1 = 109 hours
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The LCM and the HCF of the numbers 42 and 60 are in the ratio:
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