Answer:
401 more people per square mile
Explanation:
Find how many people there are per square mile in both cities by dividing the number of people by the number of square miles:
672,800/142.9
= 4708 people per square mile (Detroit)
195,100/45.3
= 4307 (Grand Rapids)
Find how many more people per square mile live in Detroit by finding the difference between these two numbers:
4708 - 4307
= 401
So, there are 401 more people per square mile living in Detroit versus Grand Rapids.