Use the following table to answer the questions listed below.
Output TC TFC TVC AFC AVC ATC MC
0 $20
10 40
20 60
30 90
40 120
50 180
60 280
a) List the total fixed costs, total variable costs, average fixed costs, average variable costs, average total costs, and marginal costs.
b) At what quantity of output does marginal cost equal average total cost and average variable cost?