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Answer : 3 24min Explanation : Answer: C) 24min Explanation: Given taps X and Y can fill the tank in 30 and 40 minutes respectively. Therefore, part filled by tap X in 1 minute = 1/30 part filled by tap Y in 1 minute = 1/40 Tap Z can empty the tank in 60 minutes. Therefore, part emptied by tap Z in 1 minute = 1/60 Net part filled by Pipes X,Y,Z together in 1 minute = [1/30 1/40 - 1/60] = 5/120 = 1/24 i.e., the tank can be filled in 24 minutes.

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