## 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