Currently, a monopolist's profit-maximizing output is 200 units per week. It sells its output at a price of $$\$ 60$$ per unit and collects $$\$ 30$$ per unit in revenues from the sale of the last unit produced each week. The firm's total costs each week are $$\$ 9,000$$. Given this information, what are the firm's maximized weekly economic profits and its marginal cost?