In 1923 , koalas were introduced on Kangaroo Island off the coast of Australia. In 1996, the population was 5000.By 2005, the population had grown to 27 ,000, prompting a debate on how to control their growth and avoid koalas dying of starvation. Assuming exponential growth , find the (continuous) rate of growth of the koala population between 1996 and 2005 . Find a formula for the population as a function of the number of years since 1996, and estimate the population in the year 2020.