Answer:
![f(x) = (729)/(3^x)](https://img.qammunity.org/2021/formulas/mathematics/high-school/llpgk9evaegbalg94tsih5fvb9bwpqes1g.png)
Explanation:
We are given the following in the question:
Number of schools in the starting of the competition = 729
Number of schools remaining after each round =
![(1)/(3)\text{ of the school in previous round}](https://img.qammunity.org/2021/formulas/mathematics/high-school/92u7zy7gya90deh6ubfjiojs46mx7nrax8.png)
We have to model an exponential function to describe the number of school remaining after x rounds.
![F(x) = 729((1)/(3))^x\\\\f(x) = (729)/(3^x)](https://img.qammunity.org/2021/formulas/mathematics/high-school/d07kua6s9fofo6nymjkrxl5mhpsm48pwes.png)
is the required function, where f(x) gives the number of school remaining after x rounds.