Park rangers released 4 fish into a pond in year 0. Each year, there were three times as many fish as the year before. How many fish were there after x years? Write a function to represent this scenario.
F ==4 * 3^x - number of fish in the pond after x years.
Example: How many fish in the pond after 3 years.
F ==4 * 3^3 ==4 * 27 ==108 fish in the pond after 3 years.