Question

Suppose the population of a country in 1985 was 145 million. In 1995 it was 190 million. Use the formula P = Ae kt to setup an expression to estimate the population of the country in 2005

Answer 1

Let t be the year in question, then

P(t) = Ae^k(t-1985)

P(1985) = Ae^0=>

A = 145

P(1995)=145e^k(1995-1985)=>

190=145e^10k=>

10k=ln(190/145)=>

k = 0.027

P(2005) = 145e^0.027(2005-1985)=>
= 145e^0.027(20)=>
= 249 million approximately.