Answer:
![P(t)=72(3)^t](https://img.qammunity.org/2021/formulas/mathematics/high-school/xcndoegku3g74pqowjsfwtv2com95x96oj.png)
Explanation:
We have to find an equation of the form
, where a is the initial value, b is the rate, and x is the time.
Here, the initial amount if 72, so a = 72. We also know that the population triples every hour, which means b = 3. Plug these in:
![P(t)=ab^t](https://img.qammunity.org/2021/formulas/mathematics/high-school/chf8qljrofmh9yuhzs8f3iqdtr2rqvuais.png)
![P(t)=72(3)^t](https://img.qammunity.org/2021/formulas/mathematics/high-school/xcndoegku3g74pqowjsfwtv2com95x96oj.png)