We know that
• The initial population is 60.
,
• There are 144 fish after 8 years.
To solve this problem, we have to use the population growth exponential expression
Where P0 is the initial population, r is the rate of growth, t is time in years, and P is the final population.
Let's use the given information to find the rate of growth (r).
Now, we solve for r
In order to solve for r, we have to apply a natural logarithm on each side so we can eliminate the power that contains r
Note that we use four decimal digits, that's because we'll get more precision.
Once, we have the rate of growth we can write the exponential function that represents the situation
<h2>(a)</h2>
On the other hand, to find the number of fish there are after 19 years, we have to use the exponential expression we found in (a).
Where t = 19, which means 19 years.
<h2>Therefore, there are 480 fish after 19 years. (b)</h2>