Answer:
Hello!! The answer for #15 is 10.9 people per square mile.
Explanation:
First, set up your equation. Then subtract left-to-right. You'll need to regroup! You can't subtract 5 from 4, so you'll need to take ten from 2. This will make your tenths place .9 and your tens place 0. Then just subtract 4 from 5 to get 1 in your ones place.
Hope this helped!!