1. **State the problem:** We want to find how many years it will take for the population of an island to double if it increases by 10% each year.
2. **Formula used:** The population growth can be modeled by the formula for exponential growth:
$$ P = P_0 (1 + r)^t $$
where $P$ is the population after $t$ years, $P_0$ is the original population, $r$ is the growth rate per year (as a decimal), and $t$ is the number of years.
3. **Set up the equation:** We want the population to double, so:
$$ 2P_0 = P_0 (1 + 0.10)^t $$
4. **Simplify the equation:** Divide both sides by $P_0$:
$$ 2 = (1.10)^t $$
5. **Solve for $t$ using logarithms:**
Take the natural logarithm of both sides:
$$ \ln(2) = \ln((1.10)^t) $$
Using the logarithm power rule:
$$ \ln(2) = t \ln(1.10) $$
6. **Isolate $t$:**
$$ t = \frac{\ln(2)}{\ln(1.10)} $$
7. **Calculate the value:**
$$ t = \frac{0.6931}{0.0953} \approx 7.27 $$
8. **Interpretation:** It will take approximately 7.27 years for the population to double at a 10% annual growth rate.
Population Doubling 1988Ac
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