For this question we can solve it by setting up a proportion:
[tex] \frac{2inches}{25 miles}= \frac{3.4inches}{x} [/tex]
Now we can solve for x to find the total distance between the towns. Let's cross multiply and solve for x:
[tex]2x=85[/tex]
[tex]x=42.5miles[/tex]
So now we know that the total distance between the towns is 42.5 miles.