3. After mining 9273 tonnes of coal, Blue Sky Mining’s managers note that the marginal cost of mining the next tonne would be

$40 per tonne. They also calculate that the user cost of mining that next tonne would be $35. If the market price of coal is

$72, should Blue Sky mine an additional tonne? [LO19B.3]

a. Yes

b. No

c. More information is needed