A population of animals starts at 212,000 and grows continuously at 5% per year to 386,289. How long does it take to achieve this growth?

We can use the exponential growth formula for continuous growth:

Final amount = Initial amount * e^(rate * time)

where:
Final amount = 386,289
Initial amount = 212,000
Rate = 0.05 (5% expressed as a decimal)
Time = unknown (to be determined)

Plugging in these values into the formula, we get:

386,289 = 212,000 * e^(0.05 * time)

Divide both sides of the equation by 212,000 to isolate the exponential term:

e^(0.05 * time) = 386,289 / 212,000

Taking the natural logarithm (ln) of both sides to eliminate the exponential term:

ln(e^(0.05 * time)) = ln(386,289 / 212,000)

Simplifying the left side of the equation:

0.05 * time = ln(386,289 / 212,000)

Now, we can solve for time by dividing both sides of the equation by 0.05:

time = ln(386,289 / 212,000) / 0.05

Using a calculator, we find:

time ≈ 16.23 years

Therefore, it takes approximately 16.23 years for the population to achieve this growth.