ECON 10223 Lecture Notes - Lecture 7: Marginal Cost

A firm is producing where its marginal costs are at the lowest level. What can one most likely infer from this? a. there is either lost opportunity for further profits by producing more, or the firm should shut-down if it is competitive and price is at that low level. b. It is a price-taker who is producing too much. c. It is a monopolist who is producing the socially optimal quantity. d. The firm is producing rationally.

6. A single-price monopolist sets price a. where MR=demand. b. where supply=demand c. from the demand curve at the quantity for which MC=MR. d. where MR=MC.

7. Assume that the Law of Diminishing Marginal Product applies at the current output level of a competitive firm. The price is $20 and, at the current output level, marginal cost is $16 and average total cost is $20. To maximize profits the firm should: a. produce the current output level, since average revenue (price) = average cost. b. produce more since marginal revenue exceeds marginal cost at current output. c. produce less since marginal revenue is always below average revenue. d. any of the above is possible, without further information.

8. Which of the following statements is true? (i) When a competitive firm sells an additional unit of output, its revenue increases by an amount less than the price. (ii) When a monopoly firm sells an additional unit of output, its revenue increases by an amount less than the price. (iii) Average revenue is the same as price for both competitive and monopoly firms. a. (i) only b. (iii) only c. (i) and (ii) d. (ii) and (iii)

9. If a firm in a competitive market triples the number of units of output sold, then total revenue will a. more than triple. b. less than triple. c. exactly triple. d. All of the above are potentially true.

10. When a competitive firm makes a decision to shut down, it is most likely that a. marginal cost is above average variable cost. b. marginal cost is above average total cost. c. price is below the minimum of average variable cost. d. fixed costs exceed variable costs.

Question 1 (1 point) Question 1 Unsaved In a competitive market the equilibrium price is determined: Question 1 options: at the intersection of the firm’s demand and the market supply curves. at the intersection of the market demand and supply curves. at the intersection of the firm’s demand and marginal cost curves. so as to cover the costs of the potential firms. so as to cover the costs of the firms currently in the industry. Save Question 2 (1 point) Question 2 Unsaved If the perfectly competitive market demand for gym shoes is given by QD = 100 – P and the market supply is given by QS = 10 + 2P, then the equilibrium price and quantity will be: Question 2 options: P = 50 and Q = 50. P = 40 and Q = 90. P = 40 and Q = 60. P = 30 and Q = 70. P = 25 and Q = 75. Save Question 3 (1 point) Question 3 Unsaved A constant-cost industry is one in which: Question 3 options: input prices do not change over time. technology does not change over time. input prices and technology do not change as firms enter or exit the industry. input prices and technology do not change over time. firms have reached the maturity phase of the industry’s life cycle. Save Question 4 (1 point) Question 4 Unsaved At the profit-maximizing level of output for the monopolist: Question 4 options: total revenue is equal to total cost. total costs are minimized. total revenue is maximized. marginal revenue is equal to marginal cost. average revenue is equal to average cost. Save Question 5 (1 point) Question 5 Unsaved Craig’s Red Sea Restaurant is the only restaurant in Columbia, South Carolina, that sells Ethiopian food. The demand for Ethiopian food is given by Q = 25 – P. Craig’s costs are given by TC = 25 + Q + 5Q2. Its maximum monopoly profit is: Question 5 options: –$1. $21. $22. $24. $26. Save Question 6 (1 point) Question 6 Unsaved So long as price exceeds average variable cost, in the model of monopolistic competition, a firm maximizes profits by producing where: Question 6 options: the difference between marginal revenue and marginal cost is maximized. marginal cost equals marginal revenue. marginal revenue equals price. the difference between price and marginal cost is maximized. price equals marginal cost. Save Question 7 (1 point) Question 7 Unsaved If a firm in a monopolistically competitive industry is profit maximizing, it should choose its level of advertising such that the marginal revenue of an additional dollar of advertising: Question 7 options: is equal to the elasticity of its demand curve minus 1. is exactly $1. increases revenues by $1. is equal to 1 plus the elasticity of its demand curve. is equal to the elasticity of its demand curve. Save Question 8 (1 point) Question 8 Unsaved Firms advertise in order to: Question 8 options: build brand loyalty. appeal to the price-sensitive consumers. increase the demand elasticities of their loyal customers. shift the market supply curve to the left. shift the market demand curve to the left. Save Question 9 (1 point) Question 9 Unsaved Firms offer promotions in order to: Question 9 options: build brand loyalty. appeal to the price-sensitive consumers. increase the demand elasticities of their loyal customers. shift the market supply curve to the left. shift the market demand curve to the left. Save Question 10 (1 point) Question 10 Unsaved If the demand increases for the product of a decreasing-cost industry: Question 10 options: short-run price goes up, but long-run price falls. long-run output goes up, but long-run price may go up or down. short-run output goes up, but long-run output may go up or down. long-run output goes up, but short-run price remains constant. long-run price goes up, but short-run price may go up or down. Save Question 11 (1 point) Question 11 Unsaved If the demand increases for the product of an increasing-cost industry: Question 11 options: short-run price goes up, but long-run price falls. long-run output goes up, but long-run price may go up or down. short-run output goes up, but long-run output may go up or down. long-run output goes up, but short-run price remains constant. short-run price goes up, and long-run price goes up. Save Question 12 (1 point) Question 12 Unsaved When Pan United Airlines gives a $400 fare discount to persons with student IDs, they are practicing: Question 12 options: first-degree price discrimination. second-degree price discrimination. third-degree price discrimination. markup pricing. tying. Save Question 13 (1 point) Question 13 Unsaved When a utility charges homeowners less than big industrial users, it is practicing: Question 13 options: first-degree price discrimination. fourth-degree price discrimination. third-degree price discrimination. markup pricing. tying. Save Question 14 (1 point) Question 14 Unsaved Cereal manufacturers’ use of coupons can be partially explained by: Question 14 options: first-degree price discrimination. second-degree price discrimination. third-degree price discrimination. markup pricing. tying. Save Question 15 (1 point) Question 15 Unsaved If a firm supplies separable markets with price elasticities h1 and h2, it should set prices P1 and P2 so that: Question 15 options: P1h1 = P2h2. P1 /h1 = P2 /h2. P1(1 + 1/h1) = P2 (1 + 1/h2). P1/(1 – 1 /h1) = P2 / (1 – 1/h2). P1 = 1 – 1/h1 and P2 = 1 – 1/h2. Save Question 16 (1 point) Question 16 Unsaved If a firm supplies separable markets with price elasticities h1 = –3 and h2 = –2, it should set prices P1 and P2 so that: Question 16 options: P1 = P2. 3P1 = 2P2. 2P1 = 3P2. 2/3P1 = 1/2P2. 2P1 = 2/3P2. Save Question 17 (1 point) Question 17 Unsaved Women are often charged more than men for haircuts performed by the same haircutter. This is not considered price discrimination because: Question 17 options: women receive more consumer surplus from haircuts than men receive. haircutters claim to spend more time on women’s hair, raising the cost of the haircut to the firm. firms make up the extra cost to consumers by giving women free samples of products. men receive more consumer surplus from haircuts than women receive. women have a lower price elasticity of demand for haircuts. Save Question 18 (1 point) Question 18 Unsaved If price is above the average variable cost but below the average total cost of a representative firm in a competitive industry: Question 18 options: there will be entry to the industry over time. there will be exit from the industry over time. the firms in the industry are just earning a normal rate of return. the firms in the industry are earning a supranormal rate of return. the industry is in long-run equilibrium. Save Question 19 (1 point) Question 19 Unsaved Joe’s T-shirts has costs given by TC = $100 + 3Q, where Q is the number of shirts. If Joe charges $5 each, the percentage markup for 100 shirts is: Question 19 options: 20%. 25%. 33%. 50%. 67%. Save Question 20 (1 point) Question 20 Unsaved In the model of monopolistic competition, there can be short-run: Question 20 options: losses or profits, but there must be profits in long-run equilibrium. profits, but there must be losses in long-run equilibrium. losses or profits, but there must be losses in long-run equilibrium. losses or profits, but there must be neither profits nor losses in long-run equilibrium. losses, but there must be profits in long-run equilibrium.

Please circle the right answer. (two points each)

1. If the price of gasoline is $2.0, and the price elasticity of demand is 0.5, how much will a 10 % reduction in the quantity placed on the market increase the price?

a.There will be 22% increase in the price

b.There will be 5% increase in the price

c.There will be 10 % increase in price

d.There will be 20% increase in price

e. None of the above

2.The consumer's budget line

a. indicates the options from which the consumer can choose

b. identifies the optimal basket for the consumer.

c. identifies the tastes of the consumer

d. ranks the baskets of goods in the order the consumer prefers them

e. shows that the consumer prefers more better than less

3. In the long run, a profit-maximizing firm will choose to exit a market when
a. fixed costs exceed sunk costs.
b. average fixed cost is rising.
c. revenue from production is less than total costs.
d. marginal cost exceeds marginal revenue at the current level of production.

4. When a perfectly competitive firm makes a decision to shut down, it is most likely that
a. price is below the minimum of average variable cost.
b. fixed costs exceed variable costs.
c. average fixed costs are rising.
d. marginal cost is above average variable cost.

5. Which of the following will always cause the demand curve for a product to shift to the right?

a. an increase in income whether the good is a compliment or substitute

b. an increase in the price of the compliment

c. an increase in the price of a substitute

d. an increase in technology

e. a decrease in the price of the good

6. Consumers understandably like lower prices, but they should understand there is a great difference between a lower price produced by the government price ceiling and a lower price that comes about through normal market channels, one benefits the consumer, the other may not.

a. This statement is not true, Consumers are benefited when the government lowers the price and the consumers are benefited when businesses lower the price.

b. This is because when the government forces prices down, there is a shortage and reduction in total surplus. Lower prices through markets don't create shortage but they do benefit consumers.

c. this is because the government forces prices down, there is a surplus and reduction in total surplus. Lower prices through markets don't create surpluses but they do benefit consumers

d. This is because when markets force the prices down, there is a shortage and reduction in total surplus. Lower prices through government actions don't create shortages but they do benefit consumers

e. None of the above

7. How does an increase in the price of a variable input affect the AC and the MC curves?

a. MC shifts to the right and AC increases.

b. MC shifts to the left and AC increases

c. MC shifts to the right and AC does not change

d. MC does not change but AC increases

e. none of the above

8. Which of the following is a characteristic of a perfectly competitive market?
a. Firms are price setters.
b. There are few sellers in the market.
c. Firms can exit and enter the market freely.
d. All of the above are correct.

9. In a perfectly competitive market, the process of entry or exit ends when
a. firms are operating with excess capacity.
b. firms are making zero economic profit.
c. firms experience decreasing marginal revenue.
d. price is equal to marginal cost.

10. The relative price of two goods is shown by:

a. the slope of an indifference curve

b. the slope of the budget line

c. the diminishing marginal rate of substitution

d. the slope of the income-consumption curve

e. none of the above

11. When firms have an incentive to exit a competitive market, their exit will

a. drive down market prices.
b. drive down the profits of existing firms in the market.
c. decrease the number of goods supplied in the market.
d. All of the above are correct.

12. If a perfectly competitive firm currently produces where the price is greater than the marginal cost, it

a. will increase its profits by producing more.
b. will increase its profits by producing less.
c. is making positive economic profits.
d. is making negative economic profits.

13. Does a consumer well being vary along a demand curve?

a. Yes. When price increases, consumers move to a lower indifference curve.

b. Yes. When price increases, consumers move to a higher indifference curve.

c. No. When price increases, consumers stay on the same indifference curve.

d. No. When price increases, the higher price has no effect on budget constraints or indifference curves.

e. None of the above

14. If a competitive firm sets its output such that marginal revenue, marginal cost, and average total cost are equal, economic profit must be:

a. Negative

b. positive

c. Zero

d. Indeterminate from the given information

15. Which of the following is a characteristic of a perfectly competitive market?

a. Firms are price setters.

b. There are few sellers in the market.
c. Firms can exit and enter the market freely.
d. All of the above are correct.