A map of a town has no scale. The actual distance between the school and the mall in the town is 5 mi., which is shown on the map as 2 in. The distance from the school to the library on the map is 1 1/2 in. What is the actual distance in miles between the school and the library?

3.75 miles

Explanation: You can solve this by thinking of proportions. When you look at 1 1/2 (or 1.5) to 2, you can see that 1.5 is 3/4 of 2. Since scales on a map are meant to be proportional to the real distance, we can use this 3/4 scale to calculate the real distance from the school to library. Simply multiply 3/4 and 5 and you will receive 15/4 or 3.75.