#### Answer

The population density of Australia is 6.8 people per square mile. This means that, on average, each square mile of Australia's land area has 6.8 people.

#### Work Step by Step

We can find the population density of Australia.
$\frac{population}{area} = \frac{20,090,400~people}{2,967,908~mi^2} = 6.8~people/mi^2$
The population density of Australia is 6.8 people per square mile. This means that, on average, each square mile of Australia's land area has 6.8 people.