Consider the following cost information for a firm that operates in a perfectly competitive market.Labor is a variable input.

Q (quantity of output) / Total cost ($)

0 / 55

2 / 100

4 / 140

6 / 200

8 / 280

10 / 380

12 / 500

(1)As the firm increase the output from 2 units to 4 units, does the marginal product of labor rise or fall?Explain.

(2) Suppose that the market price is $50.Find the optimal quantity of output that the firm should produce in the short run.

(3)Suppose that the market price drops from $50 to $30.Find the quantity of output that the firm should produce in the short run.