Let's solve this problem step-by-step. We know:
First, express the population changes in terms of equations:
Given \(P_{2022} > 100000\), substitute the value of \(P_{2021}\):
\(100000 \times \left(1 - \frac{y}{100}\right) \times \left(1 + \frac{y+10}{100}\right) > 100000\)
Cancel out 100000 from both sides:
\(\left(1 - \frac{y}{100}\right) \times \left(1 + \frac{y+10}{100}\right) > 1\)
Expand and simplify:
\(1 - \frac{y}{100} + \frac{y+10}{100} - \frac{y(y+10)}{10000} > 1\)
The linear and constant terms cancel out, so keep:
\(- \frac{y(y+10)}{10000} > 0\)
Since \(-y(y+10)\) must be positive, solve for this condition. You'll find:
\(y = 20\)
Plug \(y = 20\) into \(x = y + 10\):
\(x = 30\)
Now calculate the population in 2021:
\(P_{2021} = 100000 \times \left(1 - \frac{20}{100}\right) = 100000 \times 0.8 = 80000\)
Verify populations match all conditions. Minimizing \(P_{2021}\) requires checking other solutions, leading the lowest adequate population to adjust further:
Hence, the lowest possible population within given options is:
73000
For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is: