Answer right away. this is my last attempt

1510 vehicles

Step-by-step explanation:

First you need to determine how many feet cars and trucks occupy.

In 5 miles:

Cars fill up 80%     = 0.80 x 5 miles = 4 miles

Trucks fill up 20%  = 0.20 x 5 miles = 1 mile

Because we know the lengths and distances of the cars and trucks in feet, let's convert the miles they cover into feet.

Cars = 4 miles x 5280 ft/mile = 21,120 ft

Trucks = 1 mile x 5280 ft/mile =  5280 ft

So how many cars would there be if they covered at least 21,120 ft?

Considering that there is 3 ft between each car and a car has a length of 13.5 ft, a single car will cover 16.5 ft.

To see how many cars then fit in 21,120 ft, just divide it by the distance one car covers.

So how many trucks would there be if they covered at least 5,280 ft?

A truck is 20 ft long and again there is a space of 3 ft in between. So we add that up to see how many feet a single truck needs.

20 ft + 3 ft = 23 ft

We then take that total and divide the feet covered by trucks.

Since we cannot have half a truck, we round that off to the nearest whole number which will be 230 trucks.

So we add the number of trucks and cars to get the number of vehicles in total:

1280 + 230 = 1,510 vehicles