If the population of the world was 6.5 billion in 2006 and is currently 7.1 billion (in the year 2013), what will the population be in the year 2050?

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Answer 1 · 2017-01-16T12:10:27

10.4 billions.

There are quite many models, for population growth.

The models can be compared, for relative merits.

Here, only two starter data are available. So, I choose a 2-

parameter model. applicable for any growth.

If the year Y = 0 at 2006 and P is the population after Y years,

#P=P_0e^(kY)#

When, Y = 0, P was 6.5 billions. So, #P_0=6.5.

When it was 7 years from then, Y = 7 and

#7=6.5e^(7k)#, giving #e^(7k)=7/6.5#

On this time scale, at 2050, Y = 44, and so, P then will be

P(Y=44)

#=6.5e^(44k)#

#=6.5(e^(7k))^(44/7)#

#=6.5(7/6.5)^(44/7)#

#=10.4# billions, rounded to 3-sd.