For Part C, you need to find the year when the population would be predicted to reach seventy-five million people. You can do this by solving the equation N(t) = 75 for t. This gives you:
t = (1/k) * ln(75/N0)
For Part D, you need to find the predicted population size for the year 2025. You can do this by substituting t = 2025 - 1790 into the equation for N(t). This gives you:
N(2025) = N0 * e^(k*(2025 - 1790))
In both equations, replace N0 and k with their respective values to get the results.
