Identify the following costs as fixed or variable: Costs related to plane trips between Seattle, Washington, and Orlando, Florida, follow. Pilots are paid on a per-trip basis.

a. Pilots’ salaries relative to the number of trips flown.

b. Depreciation relative to the number of planes in service.

c. Cost of refreshments relative to the number of passengers.

d. Pilots’ salaries relative to the number of passengers on a particular trip.

e. Cost of a maintenance check relative to the number of passengers on a particular trip.

f. Fuel costs relative to the number of trips. First Federal Bank operates several branch offices in grocery stores. Each branch employs a supervisor and two tellers.

g. Tellers’ salaries relative to the number of tellers in a particular district.

h. Supplies cost relative to the number of transactions processed in a particular branch.

i. Tellers’ salaries relative to the number of customers served at a particular branch.

j. Supervisors’ salaries relative to the number of branches operated. 

k. Supervisors’ salaries relative to the number of customers served in a particular branch. 

l. Facility rental costs relative to the size of customer deposits. Costs related to operating a fast-food restaurant follow. 

m. Depreciation of equipment relative to the number of restaurants. 

n. Building rental cost relative to the number of customers served in a particular restaurant. 

o. Manager’s salary of a particular store relative to the number of employees. 

p. Food cost relative to the number of customers. 

q. Utility cost relative to the number of restaurants in operation. 

r. Company president’s salary relative to the number of restaurants in operation. 

s. Land costs relative to the number of hamburgers sold at a particular restaurant. 

t. Depreciation of equipment relative to the number of customers served at a particular restaurant.