Explanation​:
Signalling, in the context of the price mechanism, refers to how prices communicate information about the availability of resources and how they should be allocated.

The correct answer is Choice A. Prices act as signals, indicating resource scarcity when prices are high, or resource abundance when prices are low.

These answer choices do not specifically address the concept of signalling in the context of the price mechanism:

• Choice B refers to the law of demand.
• Choice C refers to the “incentive” function of price.

Choice D is incorrect because the price mechanism refers to market forces—demand and supply—not government intervention.

Explanation​:
P1​ shows the equilibrium price, or market price, for the good in the diagram, so Choice C is a true statement.

Market forces determine the equilibrium price:

• Choice A is true: the supply curve shows the marginal cost to producers of producing an additional good.
• Choice B is true: the demand curve shows the additional, or marginal, benefit consumers receive from consuming an additional good.

Choice D is an incorrect statement because P1​ is not the opportunity cost of Q1​. The opportunity cost of Q1​ is the next best choice: that choice's marginal benefit is less than P1.

Explanation​:
Statement I is incorrect: if a competing firm increases its hours, that firm is more competitive with the original firm—PED for the original firm increases.

Statement II is correct: if a competing firm begins to focus on other customers (offices), that firm is less competitive with the original firm—PED for the original firm decreases.

Statement III is correct: if the incomes of potential customers increase, the price of home cleaning will be a smaller proportion of income—PED for the service decreases.

Explanation​:
The ability to store a product affects its PES. Perishable products have lower PES, and durable products have higher PES.

Choices B, C, and D are all determinants of price elasticity of demand (PED), not PES.

Explanation​:
Statement I: In the short run, one or more factors of production are fixed. The long run is defined as the amount of time that needs to pass in order for all factors of production to be changeable.

Statement II: The marginal product curve intercepts the average product curve (AP) at the highest point of AP.

Statement III: Marginal Cost = ΔTC/Δq​

Explanation​:
Allocative efficiency occurs when the market is in equilibrium. Consumer surplus is the triangle created by the demand curve, the price, and the vertical axis.

Therefore, if the market is allocatively efficient, the price is $12 and the consumer surplus is the area of the green triangle:

(26−12) × 13/2 = $91

The following answers are incorrect because they refer to:

• (Choice A) consumer spending (12 ×13) when the price is $\text{\$}$12
• (Choice B) consumer surplus when the price is $\text{\$}$8
• (Choice D) producer surplus

A

Explanation​:
Plug the known variables into the PED formula and solve for the percentage change of quantity demanded.

−1.9=%ΔQd/−5%​

Quantity demanded increases by 9.75$\%$ when the price decreases by 5%, so eliminate choices B and D.

When prices are lowered and PED is elastic—the value is greater than 1—the total revenue will increase, so eliminate choice C. This leaves choice A as the correct answer.

Explanation​:
The diagram shows an increase of quantity supplied, which is a movement along the supply curve, not a shift. An increase in quantity supplied is caused by an increase in demand.

Choices A, B, and D are incorrect because they shift the supply curve.

• Choices A and D shift the supply curve to the left
• Choice B shifts the supply curve to the right.

Explanation​:
Statement I: A more durable product will often lead to supply being more price-elastic as producers can store inventory when prices are too low. Consequently, an increase in price causes a proportionally larger increase in quantity supplied.

Statement II: Electronics are often assembled in factories and production can be increased in a relatively short period of time.

Statement III: Availability of substitutes is a determinant of PED, not PES.

Statement IV: The degree of luxury/necessity is a determinant of PED, not PES.

Explanation​:

Choice I is incorrect: the number of substitutes for oil relates to PED, not PES

Choice II is correct: the time needed to adjust oil production inputs means that oil production does not respond to changes in price, thus making oil’s PES more inelastic

Choice III is incorrect: the cost of production is not a factor affecting PES

Choice IV is incorrect: a product being a necessity relates to PED, not PES

Explanation​:
Demand for cigarettes is likely to be inelastic because of their addictive and habit-forming nature, so most of the tax burden will likely be shifted to consumers in the form of higher prices.

Choices A, B and C are all possible outcomes of high indirect taxes on cigarettes.

A

Explanation​:
If quantity demanded changes by a greater percentage than an increase of income, it signifies that a good is a luxury good to that consumer.

On the Engel curve above, this relationship occurs when the slope of the curve is greater than 45$°$, so Choice A is an income elastic, or luxury, good.

Points B, C, and D are not luxury goods because they have slopes less than 45°.

Explanation​:
A vertical supply curve indicates that supply is perfectly inelastic, meaning quantity supplied is fixed, and supply does not respond at all to changes in price. In this case, PES = 0. The number of tickets at a sporting event will likely be fixed as the stadium will have a fixed number of seats and a maximum capacity.

Choices A and B represent products that are likely to have relatively price-elastic supply as they can be stored.

Choice D represents a product that is likely to have relatively price-inelastic supply due to the time it takes to extract, refine and process oil.

Key ideas​:

• A decrease in demand refers to a leftward shift of the demand curve.
• Only non-price determinants of demand can shift the demand curve.

Explanation​:
B is correct, as petrol and cars are complementary goods. If the price of petrol goes up, fewer people will want to buy cars (used or otherwise).

Choice A is incorrect because a rise in the price of used cars would cause a decrease of quantity demanded—a movement along the demand curve—not a shift of the demand curve.

Choices C and D are both incorrect as public transit and new cars are substitutes for used cars. Therefore, a growing distaste for public transit and a rise in price for new cars should both increase demand for used cars.

Explanation​:

A rise in the price of orange juice would decrease the quantity demanded of orange juice. As the overall demand for juice does not change, this causes an increase in demand for apple juice, as apple juice and orange juice are substitutes.

Choice A is wrong because apples are an input in the production of apple juice, so a rise in the price of apples would shift the supply curve, not the demand curve.

Choices C and D are wrong because both a fall in incomes and the emergence of new, more popular, alternatives would shift the demand curve for apple juice leftward.

Explanation​:
D is not a correct statement as it is not enough for a consumer to desire a particular good, they must also be able to purchase it in order for them to $\text{‘}$demand$\text{’}$ it.

The following statements are correct: The market demand curve is created by horizontally adding the points of all individual demand curves (Choice A).

Price is the y-axis, so anything that impacts quantity demanded besides price will cause a shift of the demand curve (Choice B).

Future price expectations are a non-price determinant of demand (Choice C).

Canned corn and corn-based ethanol are in competitive supply. If demand for corn-based ethanol increases, more corn will be allocated toward producing that instead of canned corn, causing the supply of canned corn to fall. Also, falling incomes will cause demand for canned corn to fall.

Explanation​:
I: This describes what is happening in the diagram. When price decreases, quantity demanded increases as expressed by a movement along the demand curve.

II: This does not describe what is happening in the diagram, as an increase in demand refers to a shift of the demand curve, not a movement along it.

III: The substitution effect is one of the reasons why the demand curve is downward-sloping.

Explanation​:
If bread prices are expected to rise, firms will hoard grain in anticipation, reducing supply.

Choice A is incorrect, as a change in demand for rice has no impact on the supply of bread.

Choices B and D are incorrect, as improvements in technology and favourable weather would both increase supply and cause the supply curve to shift to the right.