Humankind

The world population began to grow around 1400, after the end of the plague epidemics. In 1804, our planet reached the first billion inhabitants. In 123 years it reached the second billion. The third we managed in another 33 years, the fourth after 14, the fifth after 13, and the sixth after 12 years, in October 1999. In 2011 we will be 7 billion. The average annual increase of the last billion is approximately 1.2%.
How many billions of inhabitants will the Earth have in 2050 if we count with an average annual increase of only 1.1%?

Final Answer:

n =  10.7

Step-by-step explanation:

$$\begin{gathered} n_0=7 \\ q=1+\frac{1.1}{100}=1.011 \\ r=2050-2011=39 \\ n=n_0\cdot q^r=7\cdot 1.011^{39}=10.7 \end{gathered}$$

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