Answer:
In 2008 the US population was 4.55% of the world population.
Explanation:
In order to calculate the percent of the world population that represents the US population, we can apply a rule of three in such a way that the world population is related to 100% in the same proportion that the US population is related to x%. We then solve for x. This is shown below:
6.7*10^9 -> 100%
305*10^6 -> x%
6.7*10^9 / 305*10 ^6 = 100 / x
6.7*10^3 / 305 = 100 / x
(6.7*10^3)*x = 305*100
x = 30500 / (6.7*10^3)
x = 4,55 %
In 2008 the US population was 4.55% of the world population.