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Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins.If all of them work together, find the time taken to fill the tank
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A
17 1/7 mins
💡 Explanation:
Combined rate = 1/20 + 1/30 - 1/40 = 6/120 + 4/120 - 3/120 = 7/120 tank per minute. Time = 120/7 = 17 1/7 minutes. Pipe C empties, so its contribution is negative. The net rate determines how quickly the tank fills.