What distance would this be on the map?

Question

The scale of a map is 1 cm = 0.5 km. The distance between two towns is 10 km. What distance would this be on the map?

Answer 1

Since the distance10 km is twenty times 0.5 km, then the representation on the map would be 20 cm.

 

You could solve this, step by step, using a proportion, but I saw that it wasn't necessary.