The initial mass of a certain species of fish is 6 million tons. The mass of fish, if left alone, would increase at a rate pro
portional to the mass, with a proportionality constant of 2/yr. However, commercial fishing removes fish mass at a constant rate of 15 million tons per year. When will all the fish be gone? If the fishing rate is changed so that the mass of fish remains constant, what should that rate be?
