Answer:
The number of people that could be at the parade is 30,413 people.

Step-by-step explanation:
Given that;
The homecoming parade will run 3 miles long;

And 8 feet deep on both sides of the street;

The area of the homecoming parade is;

The number of people that could be at the parade is;

Population density is given as 6 people per 25ft^2

The number of people that could be at the parade will be;

Therefore, The number of people that could be at the parade is 30,413 people.
