12 water pumps can make a water tank empty in 20 minutes. But 2 pumps are out of order. How long will the remaining pumps take to make the tank empty?

Answer: 24 minutes
Explanation

Since 12 pumps can empty the tank in 20 minutes, the rate at which they empty the tank is 1 tank / 20 minutes.

With 2 pumps out of order, we have 12 - 2 = 10 pumps left. Since the rate is directly proportional to the number of pumps, the rate of the remaining 10 pumps is:

10/12 × (1 tank / 20 minutes) = 1 tank / 24 minutes

So, the remaining 10 pumps will take 24 minutes to empty the tank.

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