I need help some with this problem it is asking me to show my work with words

Question 2 (10 points): Suppose that the market demand for mountain spring water is given as follows: P = 1200 - Q Mountain spring water can be produced at no cost. 1. What is the prot maximizing level of output and price of a monopolist? 2. What level of output would be produced by each rm in a Cournot duopoly in the long run? What will the price be? 3. What will be the level of output and price in the long run if this industry were perfectly competitive? 4. Discuss and compare the results you found in 1, 2 and 3