Re: What difference does a few percent make?
Author: Theresa Lynn Ford
Created: Thursday, 1/27/2005 9:43 AM


What difference does a few percent make?

We are presently at 6.2 billion people.

(1) If the population growth of the world was at 3% each year how many people will there be in 20 years, by the year 2024?

Answer

The formula for
exponential growth is:
 N(t) = N(0) x ert
 
Where:
  N() is the quantity
  t is the time
  e is the natural logarithm
  r is the rate
  N(0) is the starting quantity
  N(t) is the quantity after the time has passed
 
With 6.2 billion in 2004, N(0)=6.2 and the formula is:
 N(20) = 6.2 x e(.03 x 20)
 N(20) = 6.2 x e(.6)
 N(20) = 6.2 x 1.8221188

 N(20) = 11.2971366

Therefore the population in 2024 is approximately 11.3 billion.

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