400 gallons of pesticide is accidentally spilled into a lake and uniformly mixes with the water. the volume of the lake including the pesticide is 108 gallons. a river flows into the lake bringing 5,000 gallons of fresh water per minute, and the uniform mixture spills over the dam at the same rate. how long, in minutes, will it take to reduce the pesticide in the lake to a safe level of 1 part per million gallons? (round your answer to the nearest minute.