Question

A map has a scale of 1 in : 3 km. If the actual distance is 15 km, what is the distance on the map?

Answer 1

Answer:

5 in.

Step-by-step explanation:

The ratio of map distance to real distance is 1 in : 3 km meaning that 1 inch on the map describes 15 km in real life.

15 km is 5 times 3 km, so the map distance is 5 times 1 in., or 5 in.

1 in. x 5 : 3 km x 5

This is a "school math" problem where things come out nicely!  Another way to look at this is with equivalent fractions.

$\frac{\text{1 in}}{\text{5 km}} = \frac{\text{m}}{\text{15 km}}$

"cross multiply"

$5m = (15)(1)\\5m=15\\m=3 \text{ in.}$