## Costs in the Short Run

Read this section about how to calculate costs in the short-run like variable and marginal costs. Make sure to answer the "Try It" questions.

### Average and Marginal Costs

#### Answer to Try It Questions

First Question:

- $3 per unit

Correct. $135 is the total cost for 45 units = $45 + $90 - $135. The average total cost or cost per unit = $135/45 units = $3 per unit. - $10 per unit

Incorrect. $135 is the total cost for 45 units = $45 + $90 - $135. The average total cost or cost per unit = $135 / 45 units = $3 per unit - $135

Incorrect. $135 is the total cost for 45 units = $45 + $90 - $135. The average total cost or cost per unit = $135 / 45 units = $3 per unit

Second Question:

- $18

Incorrect. $18 is the total cost of producing 3 units, the marginal cost of the 4th unit is the change in total cost ($32 - 18) = $14 - $14

Correct. The cost of producing one additional unit is the change in total cost ($32 - 18) = $14 - $32

Incorrect. $32 is the total cost of producing 4 units, the marginal cost of the 4th unit is the change in total cost ($32 - 18) = $14