It is given that the population of the fish over time is approximated by the function:
[tex]P(t)=525\ln(2t+e)[/tex]It is required to find the approximate population of the fish in 18 years.
To do this, substitute t=18 into the function:
[tex]P(18)=525\ln(2\cdot18+e)=525\ln(36+e)[/tex]Evaluate and round to the nearest whole number as required:
[tex]P(18)=525\ln(36+e)\approx1920[/tex]Hence, the fish population will be about 1920 in 18 years.