Gary sells pet rocks. His firm uses one variable input, labor, and one fixed input, his backyard. Below is his short-run production function.

Quantity of Labor	Total Product
0	0
1	12
2	30
3	50
4	66
5	70
6	70

Production Review

(a) Calculate the marginal product of the second worker. Show your work.

(b) At what range, if anywhere, does the data show increasing returns to labor? Explain.

Cost Review

(c) By the tenth unit of labor, is marginal product likely to be positive or negative? As a result, would marginal cost likely be high or low?

(d) Draw the firm's short-run average total cost curve (ATC), average fixed cost curve (AFC), average variable cost curve (AVC), and marginal cost curve (MC). (Base your graph on the traditional models for these curves, not actual cost values.)

(e) Gary's property tax decreases. Illustrate the effect of this change on your graph from part (d).

(f) The total cost for Gary's firm after the tax is $2,200, and its new total variable cost is $700. It is producing 50 units of output. Calculate the firm's average total cost. Show your work.

(g) Gary learns that to stay in business he must pay to have each pet rock inspected by a geologist. Which of the seven cost curve(s) would be affected?