A fish hatchery has500 fish at t = 0, when harvesting begins at a rate of b >0 fish/year. The fish population is modeled by the initial value problem y'(t) = 0.03y-b, y(0) = 500, where t is measured in years.

a) Find the fish population, for t>=0, in terms of the harvesting rate b.

b) Graph the solution in the case that b=90 fish/year. Describe the solution.

a) Find the fish population in terms of the harvesting rate b.