Ok so we know that the distance between City A and City B is 700 miles. We also know that 1 mile is 5280 ft, so 700 miles will be 3696000 feet. This 3696000 feet is represented on the map using 2.1 feet, so the scale of the map will be 2.1/3696000, which can be simplified by dividing both sides by 2.1 to get 1/1760000.
So we know 1 ft on the map represents 1.76 million feet in real life.
So if there are two cities which are 2000 miles apart, we can use the same scale to work out how far apart they are on the map. 2000 miles, in feet, is 2000 x 5280 = 10.56 million feet. We can multiply this by the scale to see how many feet it is on the map, which is:
10.56 million times 1/1.76 million = 6 So the cities will be 6 feet apart on the map
