1. Economics Chapter 5
Supply

2. Chapter 5
Section 2
Costs of Production

3. Economists divide a producer’s costs into fixed costs and variable costs.
A fixed cost is a cost that does not change, no matter how much is produced.
Examples of fixed costs might include rent and machinery repairs.

4. A variable cost is a cost that rises or falls depending on the quantity produced.
These include the costs of raw materials and some labor.

5. Fixed costs and variable costs are added together to find total cost.

6. A Firm’s Labor Decisions
Business owners have to consider how the number of workers they hire will affect their total production.
The marginal product of labor is the change in output from hiring one additional unit of labor, or worker.

7. Marginal Returns
There are 3 types of marginal returns

8. The First Type
Adding each worker will result in increasing marginal returns.
Increasing marginal returns occur when marginal production levels increase with new investment.
Workers will be able to specialize and gain skills.

9. The Second Type
At some point, adding each worker will result in diminishing marginal returns.
Diminishing marginal returns occur when marginal production levels decrease with new investment.

10. Workers may need to wait to use a tools or machine.
As more workers are added, there will eventually be negative marginal returns.

11. The Third Type
Marginal cost is the cost of producing one more unit of a good.
Marginal revenue is the revenue gained from producing one more unit of a good – usually, the price of a unit.

12. When marginal cost is less than marginal revenue, a producer has an incentive to increase output, since it will earn a profit on the next unit produced.

13. When marginal cost is more than marginal revenue, a producer has an incentive to decrease output, since it will lose money on the next unit produced.

14. Negative marginal returns occur when the marginal product of labor becomes negative.

15. Labor (number of workers) Marginal Product of labor
Increasing, Diminishing, and Negative Marginal Returns
Labor (number of workers)
Marginal Product of labor
(beanbags per hour) 8 7 6 5 4 3 2 1 –1 –2 –3 1 2 3
Increasing marginal returns 4 5 6 7
Diminishing marginal returns 8 9
Negative marginal returns

16. Marginal cost is the cost of producing one more unit of a good.
Marginal revenue is the revenue gained from producing one more unit of a good – usually, the price of a unit.

17. When marginal cost is less than marginal revenue, a producer has an incentive to increase output, since it will earn a profit on the next unit produced.

18. When marginal cost is more than marginal revenue, a producer has an incentive to decrease output, since it will lose money on the next unit produced.
That is why profits are maximized when marginal cost equals marginal revenue.

19. Negative marginal returns occur when the marginal product of labor becomes negative.

20. The graphic below illustrates how the marginal product of labor is derived.

21. A Summary of Production Costs

22. A fixed cost is a cost that does not change, regardless of how much of a good is produced. Examples: rent and salaries

23. Variable costs are costs that rise or fall depending on how much is produced. Examples: costs of raw materials, some labor costs.

24. The total cost equals fixed costs plus variable costs.

25. The marginal cost is the cost of producing one more unit of a good.

26. Setting Output
Marginal revenue is the additional income from selling one more unit of a good. It is usually equal to price.
To determine the best level of output, firms determine the output level at which marginal revenue is equal to marginal cost.