Neco 2020 Geography Question 46

A topographic map has a scale of 1:40,000 (1 cm on the map equals 400 m on the ground). The distance measured on the map between two successive contour lines is 2.5 cm. The map shows that the elevation at point P is 150 m and at point Q is 210 m; the road from P to Q crosses exactly three contour intervals and the map distance along the road between P and Q is 6 cm. (a) Determine the contour interval (in metres). (b) Calculate the average gradient of the road as a percentage, using the actual ground distance. Use the definition ( \frac{\text{vertical rise}}{\text{horizontal run}}\times 100\% \). (c) Classify the slope as gentle (<5%), moderate (5%-15%) or steep (>15%).