A monopolist has a constant marginal and average cost of $10 and faces a demand curve of Q(D) = 1000 - 10P. Marginal revenue is given by MR = 100 - 1/5Q.

Now suppose that the monopolist fears entry, but thinks that other firms could produce the product at a cost of $15 per unit (constant marginal and average cost) and that many firms could potentially enter. How could the monopolist attempt to deter entry, and what would the monopolists's quantity and profit be now?