Plastic and steel are substitutes in the production of body panels for certain
automobiles. If the price of plastic increases, with other things remaining the same, we
would expect:
A) the price of steel to fall.
B) the demand curve for steel to shift to the right.
C) the demand curve for plastic to shift to the left.
D) nothing to happen to steel because it is only a substitute for plastic.
E) the demand curve for steel to shift to the left.
If there are open first-class seats available on a particular flight, some airlines allow
customers with coach (discount) tickets to upgrade to first-class tickets during the
electronic check-in process. Suppose the regular price of a first-class ticket is $800, the
total price of the upgrade ticket (original price plus the upgrade) is $400, the marginal
cost of serving both types of customers (full-fare and upgrade first-class flyers) is $100,
and the airline maximizes profits. Which of the following statements is true?
A) MR for the full-fare customers must be higher than the MR from upgrade customers.
B) MR for the full-fare customers may be higher or lower than the MR from upgrades.
C) MR = MC for the full-fare customers, but the airline is willing to collect any positive
amount from the upgrade customers.
D) MR must be the same for both full-fare and upgrade customers.