Talulah is an ecologist who studies the change in the penguin population of Antarctica over time. She observed that the population decays by a factor of $\dfrac{8}{9}$ every $4$ months. The population of penguins can be modeled by a function, $P$, which depends on the amount of time, $t$ (in months). When Talulah began the study, she observed that there were $27{,}000$ penguins in Antarctica. **Write a function that models the population of the penguins $t$ months since the beginning of Talulah's study.** $P(t) = $ [[☃ expression 1]]