Final answer:
The logistic growth rate when the population is 20 million is 0.0375.
Step-by-step explanation:
The logistic growth rate for a population can be determined using the formula: r = r_max * (K - N) / K, where r is the logistic growth rate, r_max is the intrinsic growth rate, K is the carrying capacity, and N is the population size. In this case, the population is growing exponentially at a base rate of 5% per year. To find the logistic growth rate when the population is 20 million, we need to first find the intrinsic growth rate, which is 5%.
Given:
- Base exponential growth rate: 5%
- Carrying capacity: 80 million
- Population size: 20 million
Using the formula, we can calculate the logistic growth rate:
r = 0.05 * (80 - 20) / 80 = 0.05 * 60 / 80 = 0.0375
Therefore, when the population is 20 million, the logistic growth rate is 0.0375.