Suppose a company's revenue function is given by R ( q ) = − q 3 + 400 q 2 R ( q ) = - q 3 + 400 q 2 and its cost function is given by C ( q ) = 190 + 20 q C ( q ) = 190 + 20 q , where q q is hundreds of units sold/produced, while R ( q ) R ( q ) and C ( q ) C ( q ) are in total dollars of revenue and cost, respectively