chap2中级宏观经济学答案华中科技大学.doc

Microeconomics, 4e (Perloff)
Chapter 2 Supply and Demand

2.1 Demand

1) According to the Law of Demand, the demand curve for a good will
A) shift leftward when the price of the good increases.
B) shift rightward when the price of the good increases.
C) slope downward.
D) slope upward
Answer: C
Topic: Demand

2) An increase in the price of pork will lead to
A) a movement up along the demand curve.
B) a movement down along the demand curve.
C) a rightward shift of the demand curve.
D) a leftward shift of the demand curve.
Answer: A
Topic: Demand

3) An increase in consumer incomes will lead to
A) a rightward shift of the demand curve for plasma TVs.
B) a movement upward along the demand curve for plasma TVs.
C) a rightward shift of the supply curve for plasma TVs.
D) no change of the demand curve for plasma TVs.
Answer: A
Topic: Demand

4) Consider the demand function Qd = 150 - 2P. The effects of other determinants of Qd is reflected in
A) the intercept of the function.
B) the slope of the function.
C) neither the slope nor the intercept of the function.
D) in both the slope and the intercept of the function.
Answer: A
Topic: Demand

5) Consider the demand functions: A) Qd = 250 - 2P B) Qd = 300 - 3P.
Which of the demand functions reflects a higher level of consumer incomes?
A) A
B) B
C) A and B reflect the same consumer incomes.
D) More information is needed.
Answer: D
Topic: Demand

6) Holding all other factors constant, consumers demand more of a good the
A) higher its price.
B) lower its price.
C) steeper the downward slope of the demand curve.
D) steeper the upward slope of the demand curve.
Answer: B
Topic: Demand

7) As the price of a good increases, the change in the quantity demanded can be shown by
A) shifting the demand curve leftward.
B) shifting the demand curve rightward.
C) moving down along the same demand curve.
D) moving up along the same demand curve.
Answer: D
Topic: Demand

8) If the price of automobiles were to increase substantially, the demand curve for gasoline would most likely
A) shift leftward.
B) shift rightward.
C) become flatter.
D) become steeper.
Answer: A
Topic: Demand

9) If the price of automobiles were to decrease substantially, the demand curve for automobiles would most likely
A) shift rightward.
B) shift leftward.
C) remain unchanged.
D) become steeper.
Answer: C
Topic: Demand

10) If the price of automobiles were to decrease substantially, the demand curve for public transportation would most likely
A) shift rightward.
B) shift leftward.
C) remain unchanged.
D) remain unchanged while quantity demanded would change.
Answer: B
Topic: Demand

11) An increase in the demand curve for orange juice would be illustrated as a
A) leftward shift of the demand curve.
B) rightward shift of the demand curve.
C) movement up along the demand curve.
D) movement down along the demand curve.
Answer: B
Topic: Demand

12) The term "inverse demand curve" refers to
A) a demand curve that slopes upward.
B) expressing the demand curve in terms of price as a function of quantity.
C) the demand for "inverses."
D) the difference between quantity demanded and supplied at each price.
Answer: B
Topic: Demand

13) If the demand for oranges is written as Q = 100 - 5p, then the inverse demand function is
A) Q = 5p - 100.
B) Q = 20 - .2p.
C) p = 20 - 5Q.
D) p = 20 - .2Q.
Answer: D
Topic: Demand

14) To determine the total demand for all consumers, sum the quantity each consumer demands
A) at a given price.
B) at all prices and then sum this amount across all consumers.
C) Both A and B will generate the same total demand.
D) None of the above.
Answer: A
Topic: Demand

15) The above figure shows a graph of the market for pizzas in a large town. No pizzas will be demanded unless price is less than
A) $0.
B) $5.
C) $12.
D) $14.
Answer: D
Topic: Demand

For the following, please answer "True" or "False" and explain why.
16) If a good is not produced, then there is no demand for it.
Answer: False. The demand for a product is independent of its supply. It is possible that people want to buy some of the product but at prices that are below what sellers would require to begin production.
Topic: Demand

17) Because people prefer name-brand pain-relieving drugs over store-brand pain-relieving drugs, demand curves do not slope downward for pain-relieving drugs.
Answer: False. Demand curves slope downward assuming all other factors do not change. Consumers may view brand-name drugs to be of higher quality than store-brand drugs, and therefore the demand curve for brandname drugs lies to the right of the demand curve for store-brand drugs.
Topic: Demand

18) The quantity of a good that consumers demand depends only on the price of the good.
Answer: False. The quantity of a good demanded depends on many factors including: price, consumers' incomes, and the price of related goods.
Topic: Demand

19) During the winter of 1997-1998, the northeastern United States experienced warmer than usual conditions. The price of home heating oil was less than it was during the previous winter, but people bought less home heating oil. This contradicts the Law of Demand.
Answer: False. The statement claiming a contradiction confuses a change in quantity demanded with a change in the demand curve. The law of demand refers to movements along a given demand curve. The mild weather caused a leftward shift of the demand curve.
Topic: Demand

20) Suppose an individual inverse demand curve is given as P = 2 - 1/2 qi, where qi is the quantity demanded by individual i. There are 50 individual consumers with this identical, individual inverse demand curve. Solve for the market demand curve.
Answer: Solve for the individual, regular demand curve, qi = 4 - 2P. Multiply the individual demand curve by 50 to yield qD = 200 - 100P.
Topic: Demand

21) Suppose the market demand curve for pizza can be expressed as QD = 100 - 2P + 3Pb, where QD is the quantity of pizza demanded, P is the price of a pizza, and Pb is the price of a burrito. What is the slope of this demand function, and what information does the slope provide?
Answer: The slope is -2. The slope tells us how a change in the price of pizzas affects the quantity of pizzas demanded. An increase in the price of pizzas by $1 will result in a decrease of the quantity demanded by 2 pizzas.
Topic: Demand

22) Suppose the demand for a particular product can be expressed as Q = 100/p. Calculate the total amount spent on this good when p = 10, 20, and 50. Can you make a generalization about the mathematical form of this demand curve and consumer behavior in this market?
Answer: In all cases, total expenditure equals 100 (since p * Q = 100). In general, a nonlinear demand curve of the form Q = A/p means that consumers wish to spend a total of A on this good regardless of its price.
Topic: Demand

2.2 Supply

1) Suppose the demand curve for a good shifts rightward, causing the equilibrium price to increase. This increase in the price of the good results in
A) a rightward shift of the supply curve.
B) an increase in quantity supplied.
C) a leftward shift of the supply curve.
D) a downward movement along the supply curve.
Answer: B
Topic: Supply

2) A rise in the oil price will
A) shift the supply curve to the left.
B) shift the supply curve to the right.
C) leave the supply curve unchanged.
D) not enough information.
Answer: A
Topic: Supply

3) The above figure shows a graph of the market for pizzas in a large town. No pizzas will be supplied unless the price is above
A) $0.
B) $5.
C) $12.
D) $14.
Answer: B
Topic: Supply

4) Supply curves
A) slope upward.
B) slope downward.
C) are horizontal.
D) can have many shapes.
Answer: D
Topic: Supply

5) Suppose there are 100 identical firms in the rag industry, and each firm is willing to supply 10 rags at any price. The market supply curve will be a(n)
A) vertical line where Q = 10.
B) vertical line where Q = 100.
C) vertical line where Q = 1000.
D) horizontal line where Q = 1000.
Answer: C
Topic: Supply

6) The expression "increase in quantity supplied" is illustrated graphically as a
A) leftward shift in the supply curve.
B) rightward shift in the supply curve.
C) movement up along the supply curve.
D) movement down along the supply curve.
Answer: C
Topic: Supply

7) If the supply curve of a product changes so that sellers are now willing to sell 2 additional units at any given price, the supply curve will
A) shift leftward by 2 units.
B) shift rightward by 2 units.
C) shift vertically up by 2 units.
D) shift vertically down by 2 units.
Answer: B
Topic: Supply

8) The market supply curve is found by
A) horizontally summing all individual supply curves.
B) vertically summing all individual supply curves.
C) Either A or B above since they both give the same answer.
D) None of the above.
Answer: A
Topic: Supply

9) Technological innovation in the production of computers has led to
A) a decrease in the quantity demanded for computers.
B) a rightward shift of the supply curve for computers.
C) a decrease in the quantity supplied of computers.
D) None of the above.
Answer: B
Topic: Supply

10) Restricting imports tends to
A) shift the demand curve for the product to the left.
B) shift the demand curve for the product to the right.
C) change the shape of the supply curve.
D) increase the quantity supplied of a product.
Answer: C
Topic: Supply

For the following, please answer "True" or "False" and explain why.

11) The Law of Supply insures that supply curves slope upward.
Answer: False. There is no Law of Supply. Supply curves can take multiple shapes and thus don't have to be upward-sloping. (p. 22)
Topic: Supply

12) Suppose the following information is known about a market:

1. Sellers will not sell at all below a price of $2.
2. At a price of $10, any given seller will sell 10 units.
3. There are 100 identical sellers in the market.

Assuming a linear supply curve, use this information to derive the market supply curve.
Answer: First, Q = 100q since all firms are identical. This gives two points: (p = 2, Q = 0) and (p = 10, Q = 1000). From the first point, it is known that p = 2 + bQ. When Q = 1000, 10 = 2 + b(1000). Solving for b yields b = .008. Rearranging to solve for Q yields: Q = -250 + 125p or P= 2 + .008Q.
Topic: Supply

2.3 Market Equilibrium

1) Equilibrium is defined as a situation in which
A) neither buyers nor sellers want to change their behavior.
B) no government regulations exist.
C) demand curves are perfectly horizontal.
D) suppliers will supply any amount that buyers wish to buy.
Answer: A
Topic: Market Equilibrium

2) Once an equilibrium is achieved, it can persist indefinitely because
A) shocks that shift the demand curve or the supply curve cannot occur.
B) shocks to the demand curve are always exactly offset by shocks to the supply curve.
C) the government never intervenes in markets at equilibrium.
D) in the absence of supply/demand shocks no one applies pressure to change the price.
Answer: D
Topic: Market Equilibrium

3) If price is initially above the equilibrium level,
A) the supply curve will shift rightward.
B) the supply curve will shift leftward.
C) excess supply exists.
D) all firms can sell as much as they want.
Answer: C
Topic: Market Equilibrium

4) A competitive equilibrium is described by
A) a price only.
B) a quantity only.
C) the excess supply minus the excess demand.
D) a price and a quantity.
Answer: D
Topic: Market Equilibrium

5) The above figure shows a graph of the market for pizzas in a large town. At a price of $14, there will be
A) no pizzas supplied.
B) equilibrium.
C) excess supply.
D) excess demand.
Answer: C
Topic: Market Equilibrium

6) The above figure shows a graph of the market for pizzas in a large town. At a price of $5, there will be
A) excess demand.
B) excess supply.
C) equilibrium.
D) zero demand.
Answer: A
Topic: Market Equilibrium

7) The above figure shows a graph of the market for pizzas in a large town. What are the equilibrium price and quantity?
A) p = 8, Q = 60
B) p = 60, Q = 8
C) p = 14, Q = 140
D) p = 5, Q = 60
Answer: A
Topic: Market Equilibrium

8) The above figure shows a graph of a market for pizzas in a large town. At a price of $7, what is the amount of excess demand?
A) 0; there is excess supply at $7.
B) 20 units
C) 30 units
D) 10 units
Answer: C
Topic: Market Equilibrium

9) The above figure shows a graph of a market for pizzas in a large town. At a price of $10, the market
A) is not in equilibrium.
B) has excess supply.
C) does not have excess demand.
D) All of the above.
Answer: D
Topic: Market Equilibrium

10) The above figure shows three different supply-and-demand graphs. Which graph best represents the market for vacations on Mars?
A) Graph A
B) Graph B
C) Graph C
D) None of the above.
Answer: A
Topic: Market Equilibrium

11) The above figure shows three different supply-and-demand graphs. Which graph best represents the market for workers at your nearest fast-food restaurant?
A) Graph A
B) Graph B
C) Graph C
D) None of the above.
Answer: C
Topic: Market Equilibrium

12) The above figure shows three different supply-and-demand graphs. Which graph best represents the market for the air we are currently breathing?
A) Graph A
B) Graph B
C) Graph C
D) None of the above.
Answer: B
Topic: Market Equilibrium

13) After tickets for a major sporting event are purchased at the official box office price, a market often develops whereby these tickets sell at prices well above the official box office price. Which of the following scenarios would NOT be able to explain this result?
A) The official price was below equilibrium from the moment the tickets were available.
B) Increased publicity causes the demand curve for the event to shift rightward.
C) The event was not a sellout.
D) Not everyone who wanted a ticket was able to buy one at the box office.
Answer: C
Topic: Market Equilibrium

For the following, please answer "True" or "False" and explain why.

14) When a market is in disequilibrium consumers and producers change their behavior. As a result the market reaches equilibrium.
Answer: True. For example, when a shortage exists at a given price consumer bid up the price and firms increase production until the equilibrium is reached.
Topic: Market Equilibrium

15) Suppose the market for potatoes can be expressed