Ok, so:
We know that the scale given is the next one:
1cm = 7miles.
Now, let me draw something here below:
So, the cities are separated by a distance of 102.2 miles.
If 1 cm = 7 miles,
Then, we're going to convert 102.2 miles to our map scale.
102.2 miles * ( 1cm / 7 miles).
And we obtain:
14.6cm
