Week 3 Quiz

In the course's illustrative market, demand follows Qd = 90 − 10P, with P in dollars and Qd in units per day. What is quantity demanded at a price of 7 dollars?

Select one.

• 10 units per day
• 20 units per day
• 30 units per day
• 70 units per day

In the illustrative market with demand Qd = 90 − 10P, the good's price falls from 6 dollars to 5 dollars and nothing else changes. Which statement describes what happens?

Select one.

• Demand increases, so the whole demand curve shifts right
• Quantity demanded falls from 40 to 30 units along the demand curve
• Quantity demanded rises from 30 to 40 units along the demand curve
• Demand decreases, so the whole demand curve shifts left

Buyers' incomes rise, the good is a normal good, and demand in the illustrative market changes from Qd = 90 − 10P to Qd = 110 − 10P. At a price of 6 dollars, how many units do buyers now want?

Select one.

• 30 units per day
• 40 units per day
• 50 units per day
• 70 units per day

Buyers' incomes fall, the good is a normal good, and demand in the illustrative market changes from Qd = 90 − 10P to Qd = 70 − 10P. Described in words on a graph with price on the vertical axis, how does the demand curve move?

Select one.

• Left, with 20 fewer units wanted at every price
• Right, with 20 more units wanted at every price
• Down along the same line to a lower quantity
• Left, with 10 fewer units wanted at every price

True or false: an inferior good is a good of low quality.

True or false.

• True
• False

Game consoles and video games are complements. The price of game consoles rises, and nothing else changes. What happens in the market for video games?

Select one.

• Demand for games shifts right, because gamers spend more on gaming
• Demand for games shifts left, because fewer people own consoles
• Quantity demanded of games falls along an unchanged curve
• Nothing changes, because the price of games stayed the same

Which of these changes would shift the demand curve for bike-share rides? Select all that apply.

Select every option that applies.

• The price of electric-scooter rentals, a substitute, rises
• The price of a bike-share ride falls
• A new apartment building near the docks adds many new riders
• Riders come to prefer biking after a city safety campaign
• The price of a bike-share ride rises

Read the illustrative market as ten identical buyers, each wanting q = 9 − P units a day. At a price of 4 dollars, what is the market's quantity demanded?

Select one.

• 5 units per day
• 10 units per day
• 40 units per day
• 50 units per day

The law of demand says that a higher price lowers quantity demanded "with every other influence held fixed." Which idea from how economists build models does that phrase express?

Select one.

• Ceteris paribus
• Opportunity cost
• Comparative advantage
• A normative judgment

True or false: the claim that a higher price for a good lowers the quantity buyers want, all else equal, is a normative statement.

True or false.

• True
• False