Questions: A species of fish was added to a lake. The population size P(t) of this species can be modeled by the time the species was added to the lake.
P(t) = 1200 / (1 + 7 e^(-0.1 t))
Find the population size of the species after 3 years and the population size after 7 years. Round your answers to the nearest whole number as necessary.
Population size after 3 years: fish
Population size after 7 years: fish
Transcript text: A species of fish was added to a lake. The population size $P(t)$ of this species can be modeled by the time the species was added to the lake.
\[
P(t)=\frac{1200}{1+7 e^{-0.1 t}}
\]
Find the population size of the species after 3 years and the population size after 7 years. Round your answers to the nearest whole number as necessary.
Population size after 3 years: $\square$ fish
Population size after 7 years: $\square$ fish
Solution
Solution Steps
To solve this problem, we need to evaluate the given exponential function \( P(t) = \frac{1200}{1 + 7e^{-0.1t}} \) at \( t = 3 \) and \( t = 7 \). This will give us the population size of the species after 3 years and 7 years, respectively. We will use Python to perform these calculations and round the results to the nearest whole number.
Solution Approach
Define the function \( P(t) \) in Python.
Evaluate the function at \( t = 3 \) and \( t = 7 \).
Round the results to the nearest whole number.
Step 1: Define the Population Model
The population size \( P(t) \) of the species of fish in the lake is modeled by the function:
\[
P(t) = \frac{1200}{1 + 7 e^{-0.1 t}}
\]
Step 2: Calculate Population After 3 Years
To find the population size after 3 years, we substitute \( t = 3 \) into the function:
\[
P(3) = \frac{1200}{1 + 7 e^{-0.1 \cdot 3}} \approx 194
\]
Thus, the population size after 3 years is approximately 194 fish.
Step 3: Calculate Population After 7 Years
Next, we calculate the population size after 7 years by substituting \( t = 7 \):
\[
P(7) = \frac{1200}{1 + 7 e^{-0.1 \cdot 7}} \approx 268
\]
Therefore, the population size after 7 years is approximately 268 fish.
Final Answer
The population size after 3 years is \( \boxed{194} \) fish, and the population size after 7 years is \( \boxed{268} \) fish.