Consider Figure 28-7. Suppose that the monopolist is contemplating hiring 14 units of labor, which it knows would cause the marginal product to decline to 150 units of output per unit of labor. As a result, the product price would decrease to $4.50 per unit, and the firm's marginal revenue would decline to $3.20n per unit. What would be the firm's marginal revenue product if it hires a 14th unit of labor?