High School Economics Quiz: Cost Categories
20 questions · exam conditions
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Cost CategoriesQuestion 1 of 20

If a firm's average total cost is decreasing as output increases, which of the following statements must be true?

Marginal cost must be less than average total cost.
Total fixed cost must be decreasing.
Average variable cost must be decreasing.
Total variable cost must be decreasing.
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High School Economics Quiz

High School Economics Quiz: Cost Categories

Practice Cost Categories in High School Economics with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Cost Categories, giving you a quick way to practice the rules, question types, and explanations that matter most for High School Economics.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

If a firm's average total cost is decreasing as output increases, which of the following statements must be true?

  1. Marginal cost must be less than average total cost. (correct answer)
  2. Total fixed cost must be decreasing.
  3. Average variable cost must be decreasing.
  4. Total variable cost must be decreasing.
Explanation: This question connects cost categories to marginal analysis. For an average to be falling, the marginal value being added must be below the current average. Therefore, if average total cost (ATC) is decreasing, the marginal cost (the cost of the next unit) must be less than the ATC. Total fixed cost is constant by definition. Average variable cost could be increasing (as long as the decline in average fixed cost is greater). Total variable cost must be increasing if output is increasing.

Question 2

A consulting firm requires one senior consultant, whose salary is $10,000 per month, for every five projects it manages. The firm also has administrative and rent costs of $20,000 per month. If the firm increases its workload from 8 projects to 11 projects in a month, how would its costs be categorized?

  1. The entire increase in cost is classified as a variable cost.
  2. The cost of consultants is a variable cost, while rent is a fixed cost.
  3. The cost of consultants is a step-fixed cost, and rent is a fixed cost. (correct answer)
  4. Both consultant salaries and rent are fixed costs in the short run.
Explanation: Rent is a fixed cost as it doesn't change with the number of projects. The consultant cost is a step-fixed cost. At 8 projects, the firm needs two consultants (one for 1-5, a second for 6-10). At 11 projects, it needs a third consultant. The cost doesn't vary per project but jumps at certain output levels. This distinguishes it from a purely variable cost (which changes with each unit) and a purely fixed cost (which doesn't change at all within a range).

Question 3

A manufacturing firm produces 500 units at a total cost of $12,000. The firm's total fixed cost is $4,000. If the firm increases production to 600 units and its average variable cost remains constant, what will be the new total cost?

  1. $13,600 (correct answer)
  2. $12,000
  3. $14,400
  4. $9,600
Explanation: First, calculate the initial total variable cost (TVC): TVC = Total Cost - Total Fixed Cost = $12,000 - $4,000 = $8,000. Second, calculate the average variable cost (AVC): AVC = TVC / Quantity = $8,000 / 500 units = $16 per unit. Third, calculate the new TVC at 600 units: New TVC = AVC * New Quantity = $16 * 600 = $9,600. Finally, calculate the new total cost: New Total Cost = Total Fixed Cost + New TVC = $4,000 + $9,600 = $13,600.

Question 4

A company shifts its sales force compensation model from a fixed annual salary for each salesperson to a model based purely on commission (a percentage of sales revenue). How would this change affect the company's cost structure, assuming total sales volume remains the same?

  1. It increases total costs by introducing a new variable cost component.
  2. It decreases fixed costs and increases variable costs, altering the cost mix. (correct answer)
  3. It decreases variable costs and increases fixed costs, making costs more predictable.
  4. It has no effect on the cost structure, as the total compensation paid remains the same.
Explanation: Fixed annual salaries are a fixed cost because they do not vary with the level of sales. A commission-based system is a variable cost because the total amount paid out varies directly with the amount of sales (output). By switching from salaries to commissions, the company is converting a fixed cost into a variable cost. This lowers its total fixed costs and increases its total variable costs.

Question 5

A power company invests $2 billion to build a nuclear power plant. The cost of uranium fuel to generate one megawatt-hour (MWh) of electricity is $10. The plant has a monthly insurance and security cost of $1 million. Which of the following costs is a variable cost for the company?

  1. The $2 billion construction cost, amortized over the life of the plant.
  2. The $1 million monthly insurance and security cost.
  3. The combined cost of construction, insurance, and security.
  4. The $10 cost of uranium fuel for each MWh generated. (correct answer)
Explanation: Variable costs change with the level of output. The cost of uranium fuel is directly tied to the amount of electricity (MWh) generated, so it is a variable cost. The construction cost is a sunk/fixed cost. The monthly insurance and security cost is a fixed cost because it is paid regardless of how much electricity is generated in that month. The combined cost in D is a mix, but the question asks to identify a variable cost.

Question 6

A farm's total cost for a harvest is $200,000. Its total variable costs, including seeds, fertilizer, and seasonal labor, are $120,000. The harvest yields 40,000 bushels of wheat. What is the farm's average fixed cost per bushel?

  1. $2.00 (correct answer)
  2. $3.00
  3. $5.00
  4. $8.00
Explanation: First, calculate the total fixed cost (TFC). TFC = Total Cost - Total Variable Cost = $200,000 - $120,000 = $80,000. Next, calculate the average fixed cost (AFC) by dividing the TFC by the quantity of output. AFC = TFC / Quantity = $80,000 / 40,000 bushels = $2.00 per bushel.

Question 7

A restaurant's total costs are $30,000 per month when it serves 2,000 meals. Of this amount, $10,000 represents fixed costs such as rent and insurance. If the restaurant serves 2,500 meals next month and experiences the same cost structure, what will its average total cost per meal be?

  1. $10.00
  2. $12.00
  3. $14.00 (correct answer)
  4. $15.00
Explanation: Step 1: Find the variable cost per meal. Initial TVC = $30,000 - $10,000 = $20,000. Initial AVC = $20,000 / 2,000 meals = $10 per meal. Step 2: Calculate the new total cost. New TVC = 2,500 meals * $10/meal = $25,000. New TC = TFC + New TVC = $10,000 + $25,000 = $35,000. Step 3: Calculate the new average total cost. New ATC = New TC / New Quantity = $35,000 / 2,500 meals = $14 per meal.

Question 8

A courier company owns a fleet of delivery vans. Which of the following two costs associated with the fleet are best described as a fixed cost and a variable cost, respectively?

  1. Monthly vehicle insurance payments and the cost of gasoline. (correct answer)
  2. The cost of gasoline and the cost of purchasing new tires.
  3. The driver's hourly wages and the monthly vehicle insurance payments.
  4. The original purchase price of the vans and the driver's hourly wages.
Explanation: A fixed cost does not vary with the level of activity (deliveries), while a variable cost does. Monthly vehicle insurance payments are typically a flat rate per vehicle, regardless of how many miles are driven, making it a fixed cost. The cost of gasoline is directly related to the miles driven, which corresponds to the level of output (deliveries), making it a variable cost.

Question 9

A firm that produces skateboards has total fixed costs of $3,000 per month. At an output of 300 skateboards, the firm's average total cost is $25. What is the firm's total variable cost at this level of output?

  1. $7,500
  2. $4,500 (correct answer)
  3. $10,500
  4. $15
Explanation: First, calculate the total cost (TC) at an output of 300 skateboards. TC = Average Total Cost * Quantity = $25 * 300 = $7,500. Next, use the relationship TC = Total Fixed Cost + Total Variable Cost to find the total variable cost (TVC). TVC = TC - TFC = $7,500 - $3,000 = $4,500.

Question 10

A firm has an average fixed cost (AFC) of $5 and an average variable cost (AVC) of $20 when it produces 1,000 units. If the firm decides to produce one additional unit, and its marginal cost for that unit is $22, what is the firm's total cost at an output of 1,001 units?

  1. $25,000
  2. $25,022 (correct answer)
  3. $27,000
  4. $25,027
Explanation: First, calculate the total cost at 1,000 units. Total Fixed Cost (TFC) = AFC * Q = $5 * 1,000 = $5,000. Total Variable Cost (TVC) = AVC * Q = $20 * 1,000 = $20,000. Total Cost (TC) = TFC + TVC = $5,000 + $20,000 = $25,000. Marginal cost is the additional cost of producing one more unit. Therefore, the total cost of producing 1,001 units is the TC of 1,000 units plus the marginal cost of the 1,001st unit: $25,000 + $22 = $25,022.

Question 11

A small airline operates a single route. The monthly cost to lease the aircraft is $200,000, and the pilots' and cabin crew's salaries total $80,000 per month. Fuel, landing fees, and passenger-specific taxes cost $10,000 per flight. The airline currently operates 40 flights per month. If the airline reduces its schedule to 30 flights next month, what will be its estimated total cost?

  1. $580,000 (correct answer)
  2. $300,000
  3. $525,000
  4. $680,000
Explanation: First, identify the fixed and variable costs. The fixed costs are the aircraft lease and crew salaries, which do not depend on the number of flights: TFC = $200,000 + $80,000 = $280,000. The variable cost is $10,000 per flight. For 30 flights, the total variable cost will be: TVC = 30 flights * $10,000/flight = $300,000. The new total cost is the sum of the total fixed and total variable costs: TC = TFC + TVC = $280,000 + $300,000 = $580,000.

Question 12

A bicycle assembly plant has a daily fixed cost of $5,000, which includes rent and administrative salaries. The variable cost per bicycle, for parts and labor, is $75. On Monday, the plant produces 100 bicycles. On Tuesday, it produces 120 bicycles. What is the change in the total cost from Monday to Tuesday?

  1. $1,500 (correct answer)
  2. $14,000
  3. $2,500
  4. $12,500
Explanation: The change in total cost is driven entirely by the change in total variable cost, as fixed costs do not change with output. The change in output is 120 - 100 = 20 bicycles. The change in total cost is the change in output multiplied by the variable cost per unit: 20 bicycles * $75/bicycle = $1,500. Alternatively, one could calculate total cost for each day and find the difference: TC(Mon) = $5,000 + (100 * $75) = $12,500. TC(Tues) = $5,000 + (120 * $75) = $14,000. The change is $14,000 - $12,500 = $1,500.

Question 13

A firm that produces custom t-shirts pays $1,000 per month in rent for its workshop. The blank shirts cost $4 each, and the printing ink costs $1 per shirt. If the firm's output decreases from 500 shirts to 400 shirts in a month, which of the following will occur?

  1. Total fixed cost will decrease, and average variable cost will decrease.
  2. Total variable cost will decrease, and average fixed cost will increase. (correct answer)
  3. Total cost will remain the same, but average total cost will increase.
  4. Both total variable cost and total fixed cost will remain unchanged.
Explanation: Total fixed cost ($1,000 rent) does not change with output. Total variable cost (TVC) is (4+1)Q = $5Q. When Q decreases from 500 to 400, TVC decreases from $2,500 to $2,000. Average fixed cost (AFC) is TFC/Q. When Q decreases, AFC increases (from 1000/500=1000/500=2 to 1000/400=1000/400=2.50). Therefore, total variable cost decreases and average fixed cost increases.

Question 14

A call center pays a monthly salary to its 10 administrative staff members. It also pays its customer service agents based on the number of hours they work, which varies with call volume. The center signs a new contract for phone services that includes a flat monthly fee of $2,000 plus a charge of $0.01 per minute of call time. How does this new phone service contract affect the center's cost structure?

  1. It only increases total variable costs, as all phone charges are tied to usage.
  2. It only increases total fixed costs, as the contract is a recurring monthly expense.
  3. It increases both total fixed costs and total variable costs for the call center. (correct answer)
  4. It converts some of the firm's fixed labor costs into variable phone costs.
Explanation: The new contract has two components. The $2,000 flat monthly fee is a fixed cost because it must be paid regardless of call volume. The $0.01 per-minute charge is a variable cost because it increases as the total minutes of call time (driven by output) increase. Therefore, the new contract adds to both the fixed and variable costs of the firm.

Question 15

A book publisher has a total cost function represented by the equation TC=50000+5QTC = 50000 + 5Q, where QQ is the number of books produced. If the publisher produces 10,000 books, what are the firm's total variable cost and total fixed cost, respectively?

  1. $50,000 and $50,000 (correct answer)
  2. $5 and $50,000
  3. $100,000 and $50,000
  4. $50,000 and $100,000
Explanation: In a linear total cost function TC=TFC+VC(Q)TC = TFC + VC(Q), the constant term represents the total fixed cost (TFC) and the term that varies with quantity (Q) represents the total variable cost (TVC). Here, TFC = $50,000. The variable cost per unit is $5, so the total variable cost is 5Q5Q. At an output of Q = 10,000, the TVC is (5 * 10,000 = $50,000). So the total variable cost is $50,000 and the total fixed cost is $50,000.

Question 16

A firm is considering a temporary shutdown for one month, meaning its output will be zero. During the shutdown, the firm will not purchase raw materials or pay its hourly workers. However, it must still make payments on its factory lease and property taxes. The firm's total costs during the shutdown month will be equal to its

  1. total variable costs from the previous month of operation.
  2. average total cost multiplied by the planned output for the next month.
  3. total fixed costs, as these are independent of the level of output. (correct answer)
  4. zero, since no production is occurring during the shutdown.
Explanation: By definition, fixed costs are costs that do not vary with the level of output. Even when output is zero, these costs must be paid in the short run. Variable costs (raw materials, hourly labor) are zero when output is zero. Therefore, the firm's total cost during a temporary shutdown is equal to its total fixed costs.

Question 17

A government imposes a new annual licensing fee of $1,000 on all businesses in a specific industry, regardless of their size or sales volume. Simultaneously, it introduces a tax of $0.50 for each unit the business sells. How do these two government actions affect a firm's costs?

  1. Both actions increase the firm's fixed costs.
  2. Both actions increase the firm's variable costs.
  3. The fee increases fixed cost, while the tax increases variable cost. (correct answer)
  4. The fee increases variable cost, while the tax increases fixed cost.
Explanation: The $1,000 annual licensing fee is a fixed cost because it is a lump-sum amount that does not change with the firm's level of production or sales. The $0.50 per-unit tax is a variable cost because the total amount of tax paid by the firm is directly proportional to the number of units it sells.

Question 18

A local coffee shop roasts its own beans. The owner has a one-year lease on the building and equipment. A new brewing machine becomes available that reduces the amount of coffee beans required per cup by 20% but costs the same as the old machine. From a cost perspective, when would this new machine change the shop's variable costs but not its fixed costs?

  1. In the long run, when the owner can decide whether to switch to the new machine.
  2. Immediately, because the reduction in bean usage lowers costs regardless of the lease.
  3. Only after the one-year lease expires and the owner can replace the equipment without penalty. (correct answer)
  4. Never, because the cost of the machine is a fixed cost and the cost of beans is a variable cost.
Explanation: The one-year lease makes the current equipment a fixed cost in the short run (within the year). The owner cannot change this cost without penalty. The cost of coffee beans is a variable cost. The new machine affects the variable cost (beans per cup). The owner can only act on this change—replacing the machine—after the short-run constraint (the lease) expires. At that point, the equipment cost is no longer fixed, but the decision to purchase it affects the ongoing variable costs.

Question 19

A software company spends $2 million developing a new application. The company pays a 30% commission to a digital marketplace for each copy sold. The company has also signed a five-year, $500,000 per year contract for office space and server hosting.

Which of the following best describes the immediate effect on the company's cost structure if a new regulation requires an annual compliance audit costing $50,000?

  1. The variable cost per unit sold will increase, but the total fixed costs will remain unchanged.
  2. The total fixed costs will increase, but the variable cost per unit sold will remain unchanged. (correct answer)
  3. Both the total fixed costs and the variable cost per unit sold will increase.
  4. The sunk cost of development will increase, while other costs remain unaffected.
Explanation: The annual compliance audit is a cost that does not vary with the number of units sold. Therefore, it is a fixed cost. This increases the firm's total fixed costs (which already include the office/server contract). The variable cost, which is the 30% commission per sale, is not affected by the new audit requirement.

Question 20

A key distinction between the short run and the long run for a firm is that in the long run,

  1. all costs become fixed costs because the firm has committed to a scale of production.
  2. total costs are always lower than in the short run due to technological advances.
  3. variable costs become fixed, while fixed costs become variable.
  4. all costs are considered variable costs, as the firm can adjust all inputs. (correct answer)
Explanation: The defining characteristic of the long run in production and cost theory is that it is a period of time sufficient for a firm to change the quantities of all its inputs. This means there are no fixed inputs or fixed costs; the firm can alter its factory size, machinery, and other factors that are fixed in the short run. Therefore, in the long run, all costs are variable.