What is the population density of a country with a total population of 140,000,000 and a total land area of 500,000 km2?

Analyze the question You are asked for population density, which tells us how many people live on average in each square kilometre of a country.

The concept

Population density = Total population ÷ Total land area

Solution

• Total population = 140,000,000
• Land area = 500,000 km²

Population density = 140,000,000 ÷ 500,000

Cancel the zeros (divide both by 100,000):

= 1,400 ÷ 5

= 280 persons per km²

Checking the options

• A. 280 persons per km², which matches our working.
• B. 200 would need a population of 100,000,000.
• C. 350 would need a population of 175,000,000.
• D. 500 would need a population of 250,000,000.

Tip For density questions, cancel the same number of zeros from the top and bottom first, then divide. This makes the arithmetic quick and reduces mistakes in the exam hall. Also remember that the unit is always "persons per km²", which is people divided by area.