The population of the world was approximately 6.3 billion in July 2003. Assuming that the population will grow by 2% each year, estimate the following.
In what year will the population of the world double?
The model you need is
$\displaystyle P = 6,300,000,000\times 1.02^t$ where P is population and t is years.
You need to solve for t when P has doubled i.e. 12,600,000,000.
So $\displaystyle 12,600,000,000 = 6,300,000,000\times 1.02^t$
$\displaystyle 2 = 1.02^t$ Can you solve it from here?
Spoiler: