Question

Pre-Calculus question:

Assuming a current world population of 6 billion people, an annual growth rate of 1.9% per year, and a worst-case scenario of exponential growth, what will the world population be in 50 years?
a) 15.38 Billion
b) 18.73 Billion
c) 14.25 Billion
d) 16.45 Billion

I think that I need to use the exponential growth formula: P(t)=P₀a^t where P₀=6 billion and t=50 years but not sure what a (the base) is nor how to use the annual growth rate 1.9% information.

Answer 1

You already have figured the main idea. In this case, the population is growing 1.9% a year. This word can be translated into: multiplied by 101.9% (100+1.9%). That means the P0 is 6 bill, the base is 101.9%(or 1.019) and the time is 50 years. The calculation would be:
P(t)=P₀a^t
P(t)=6 billion * 101.9%^50= 6 billion * 2.56276= 15.38 billion