A map of Nigeria has a scale of 1:2,000,000. If the straight-line distance between Abuja and Kaduna on the map is 5 cm, what is the actual ground distance in kilometres?

Using the representative fraction: actual distance = map distance × scale denominator = 5 cm × 2,000,000 = 10,000,000 cm. Converting to kilometres: 10,000,000 ÷ 100,000 = 100 km. The actual ground distance between the two points is therefore 100 km.