Explanation and Steps:
So if 1 inch is 16 miles and we have to figure out how many inches is 20 miles, we should find how many inches is 1 mile to start. To do that, we will do 1 divided by 16, which is 0.0625. So 1 mile is 0.0625 inches.
Now let's check to see if the math was correct. Take 0.0625 and multiply it by 16. If you get 1, it's correct, if not, it's incorrect. (0.0625)(16)=1. That is correct! So now that we know 0.0625 inch is equal to 1 mile, we can find how many inches is 20 miles by multiplying 0.0625 and 20. (0.0625)(20)=1.25
1.25 inches on the map represents 20 miles.
Work (Answer):
1in=16mi
1in/16mi=0.0625in/mi
(0.0625in/mi)(20mi)=1.25in
Hope this helped!