A firm is producing 200 units of output at a total cost of $1,000 . The firm's average variable cost equals $4 per unit. Total fixed cost:
a. equals $1,000.
b. equals $800

Why does the United States both import and export ethanol?

a. U.S. regulations require U.S. fuel companies to use both ethanol made from corn and ethanol made from other sources (such as sugar), which has led to a surplus of corn ethanol that is exported to Brazil in return for sugar ethanol. b. U.S. regulations require U.S. fuel companies to use only ethanol made from corn, which has led to a surplus of corn ethanol that is exported to Brazil. c. Brazilian regulations require its fuel companies to use both ethanol made from corn and ethanol made from sugar, which has led to a surplus of sugar ethanol that is exported, and a need for corn ethanol, which is imported from the United States. d. Brazilian regulations require its fuel companies to use only ethanol made from corn, which has led to a surplus of sugar ethanol that is exported, and a need for corn ethanol, which is imported from the United States.

For the perfectly competitive firm, economic profit equals:

a. (price - marginal cost) x quantity. b. (price - average total cost) x quantity. c. (price - average variable cost) x quantity. d. total revenue - total fixed cost.