Consider a market with the following inverse demand function, p = 140 - 3Q and constant marginal cost = 20.

1. Write down the total revenue (TR) function and the marginal revenue (MR) function (in terms of Q).

2. Write down the total cost (TC) function and the marginal cost function.

3. Find the profit maximizing quantity and price

4. What is the firm's profit?

Profit Maximization

Consider an industry with a linear inverse demand, p = 300 - 2Q, and MC = AC = $60. Solve for industry output (Q), price (p), and profits if the industry is:

1. Perfectly competitive

2. Monopolistic