A map has a scale of 6 cm : 20 km. Which statement is true?

Question 3 options:

Two cities that are 15 cm apart on the map are actually 50 km apart.

Two cities that are 50 cm apart on the map are actually 15 km apart.

Two cities that are 10 cm apart on the map are actually 24 km apart.

Two cities that are 240 cm apart on the map are actually 24 km apart.

1 answer

To solve this problem, we need to understand the scale of the map, which is 6 cm : 20 km. This means that every 6 cm on the map corresponds to 20 km in reality.

First, let's calculate the actual distance represented by 1 cm on the map:

\[ \text{If } 6 \text{ cm represents } 20 \text{ km, then } 1 \text{ cm represents } \frac{20 \text{ km}}{6} = \frac{10}{3} \text{ km} \approx 3.33 \text{ km.} \]

Now we can apply this to each statement:

  1. Two cities that are 15 cm apart on the map are actually 50 km apart.

    • Actual distance = 15 cm * (20 km / 6 cm) = 15 * (20/6) km = 50 km.
    • This statement is TRUE.
  2. Two cities that are 50 cm apart on the map are actually 15 km apart.

    • Actual distance = 50 cm * (20 km / 6 cm) = 50 * (20/6) km = 166.67 km.
    • This statement is FALSE.
  3. Two cities that are 10 cm apart on the map are actually 24 km apart.

    • Actual distance = 10 cm * (20 km / 6 cm) = 10 * (20/6) km = 33.33 km.
    • This statement is FALSE.
  4. Two cities that are 240 cm apart on the map are actually 24 km apart.

    • Actual distance = 240 cm * (20 km / 6 cm) = 240 * (20/6) km = 800 km.
    • This statement is FALSE.

Based on the calculations, the only true statement is:

"Two cities that are 15 cm apart on the map are actually 50 km apart."