The manager of a local monopoly estimates that the elasticity of demand for its product is constant and equal to -4, a. Express the firm’s marginal revenue as a function of its price: b. Determine the profit-maximizing price.

The manager of a local monopoly estimates that the elasticity of demand for its product is constant and equal to -4. The firm’s marginal cost is constant at $20 per unit (round all responses to two decimal points)

a. Express the firm’s marginal revenue as a function of its price:
b. Determine the profit-maximizing price.