the question is in the description it wouldn't fit

Question

The population of the world was 5.7 billion in 1995, and the observed relative growth rate was 2% per year.
(a) By what year will the population have doubled?


(b) By what year will the population have tripled?

Answer 1

2(5.7) = 5.7(1.02)^t                 divide both sides by 5.7

2 = 1.02^t                                take natural log of both sides

ln 2 = t ln 1.02                       calculate

0.693147181 ≈ 0.0198 t        divide both sides the 0.0198

35 ≈ t

 

It takes 35 years for the population to double.

 

Answer (b) by changing the 2 to a 3.