A map drawn to a scale of 1:100,000 is enlarged so that its linear scale becomes 1:25,000. By what factor has the area of the map increased?

The linear scale has been enlarged by a factor of 100,000 ÷ 25,000 = 4. Because area is a two-dimensional measure, the area increases by the square of the linear factor: 4² = 16. Many candidates incorrectly choose 4, confusing the linear enlargement factor with the area enlargement factor.