The population of a town was 5,000 in 2000 and grew to 9,000 in 2010.

Question

Assume that the population will continue to grow exponentially at the same constant rate. What will the population of the town be in 2020? 

Answer 1

Over ten years, population grew by a factor 1.8 (since 4/5 is 8 tenths). (The amount of increase was 0.8 times base population).

 

So just multiply 2010's population, nine thousand, by 1.8 to get 2020's population. (Or wait 3 years + 1 month & count people!)

 

Do you get answer 16,200?