Appalachian Coal Mining believes it can increase labor productivity and, therefore, net revenue by reducing air pollution i its mines. It estimates that the marginal cost function for reducing pollution by installing additional capital equipment is MC=40P where P represents a reduction of one unit of pollution in the mines. It also feels that for every unit of pollution reduction the marginal increase in revenue (MR) is MR=1000-10P. How much pollution reduction should Appalachian Coal Mining undertake?