Question

Out of a world population of approximately 6.6 billion, 1.2 billion people live in the richer countries of Europe, North America, Japan and Oceania and is growing at the rate of 0.25% per year, while the other 5.4 billion people live in the lees developed countries and is growing at the rate of 1.5%. What will be the world population in 5 years if we assume that these rates of increase will stay constant for the next 5 years.

Answer 1

Let us first calculate the population PR in 5 years in the richer countries

PR = (1.2 + 0.25% * 1.2) = 1.2(1 + 0.25%) after one year

PR = 1.2(1 + 0.25%) + 0.25% * 1.2(1 + 0.25%)

= 1.2(1 + 0.25%) ² after two years

Continue with the above and after 5 years, PR will be

PR = 1.2(1 + 0.25%)5 5 years

Similar calculations can be used to find the population PL in less developed countries after 5 years.

PL = 5.4(1 + 1.5%)5 after 5 years

The world population P after 5 years will be

P = PR + PL = 1.2(1 + 0.25%)5 + 5.4(1 + 1.5%)5 = 7.03 billion.

7.03 billion people