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A water pump for a dredging project can remove 180 gallons of water per minute, but can work only for 3 consecutive hours, at which time it requires 20 minutes of maintenance before it can pump 80 gallons per minute. While it is offline, a smaller pump is used in its place, which can pump 80 gallons per minute. Using this system, the least amount of time it would take to pump 35,800 gallons of water.
What is 3 hours and 30 minutes?