Can anyone make up an example for me (ratios)?

A 1:20,000 scale is not the same as a 1" = 20,000' scale. It means 1" = 20,000".

Say two points on a map at that scale are 1 1/4" apart. Then in the real world, they would be 20,000 times that far apart.

20,000 times 1 1/4" = 25,000 inches. To convert to feet, just divide that by 12. 25,000" / 12" per foot = 2,083 1/3 feet.

My intention here is to show you examples; without giving you the result of your actual problem:

See attached web link:

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"Map Scales"

If a map has a scale of 1 : 50 000

This means that 1 unit on the map is actually 50 000 units across the land.

So 1cm on the map is 50 000cm along the ground (= 0.5km). So 1cm on the map is equivalent to half a kilometre in real life.

For 1 : 25 000 - 1 unit on the map is the same as 25 000 units on the land.

So 1 inch on the map represents 25 000 inches across the land

Or 1cm on the map represents 25 000 cm in real life.

You can manipulate these ratios if necessary.

Draw a line 10 inches long to represent 20,000 miles/Km or whatever units. Each inch represents 2,000 units.