To interpret \( P(4) = 843.75 \) accurately:
The function \( P(n) = 54(2.5)^{n-1} \) calculates the population of insects in the \( n \)-th generation, starting from 54 insects in the first generation.
When we evaluate \( P(4) \):
- The input \( n = 4 \) indicates we are looking for the population in the 4th generation.
- The output \( P(4) = 843.75 \) means that there are approximately 843.75 insects in the 4th generation.
Since insect populations are typically considered as whole numbers, we interpret this as an indication of growth, even if the specific number isn't a whole insect.
Thus, the correct interpretation is:
There were 843 insects in the 4th generation.