答案和详解如下：

1.Which of the following is least accurate regarding the relationship between price (P), marginal revenue (MR), average total cost (ATC), and marginal cost (MC) at the profit maximizing output under monopoly?

A)   P = MR

B)   MR = MC.

C)   P > MC.

D)   MR < ATC.

The correct answer was A)

To maximize profit, all firms expand output until marginal revenue equals marginal cost. Price is determined from the demand curve, which is above the marginal revenue curve since a monopoly faces a downward sloping demand curve.

2.What is the relationship between price and marginal revenue for a price searcher?

A)   Marginal revenue > price.

B)   Marginal revenue < price.

C)   Marginal revenue = price.

D)   There is no relationship between marginal revenue and price.

The correct answer was B)

For a price searcher, demand is downward sloping, marginal revenue is less than price since price must be reduced to sell additional units of output.

3.Which of the following is least relevant when explaining why monopoly firms can earn positive economic profits over the long term?

A)   The ability to use price discrimination.

B)   The existence of economies of scale.

C)   Control over production input resources.

D)   Licensing agreements and patents.

The correct answer was A)

High entry barriers due to economies of scale, government licensing, resource controls, and patents prevent new firms from entering the market to exploit positive economic profit opportunities.

4.Monopolists will maximize profit by producing at an output level where which of the following conditions exists?

A)   Price = marginal revenue = marginal cost.

B)   Price = demand = marginal revenue = marginal cost.

C)   Marginal revenue = average total cost = price.

D)   Marginal revenue = marginal cost < price.

The correct answer was D)    

To maximize profit, monopolists will expand output until marginal revenue equals marginal cost. Price will be greater than marginal revenue because a monopolist faces a downward sloping demand curve.

5.At an output quantity equal to 250, a monopoly firm faces a demand curve with a price (P) of $50, a marginal cost (MC) and marginal revenue (MR) equal to $10, and an average total cost (ATC) equal to $12. The economic profit for this monopoly firm is closest to:

A)   $12,500.

B)   $10,000.

C)   $12,000.

D)   $9,500.

The correct answer was D)

Economic profit = Total revenue – total cost, where total revenue = PQ and total cost = ATC x Q. So, Economic profit = $9,500 = ($50)(250) – ($12)(250).