The Population Growth of a Certain Geographic Region Is Defined $$f ( t ) = A _ { 0 } ( 1.8 ) ^ { t } ,$$

The population growth of a certain geographic region is defined by the function
$$f ( t ) = A _ { 0 } ( 1.8 ) ^ { t } ,$$
where $A _ { 0 }$ is the population at time $t = 0$ , and $t$ is the time in decades. If the present population is 27,000 , find the population in 60 years. [Hint: A decade is 10 years.]