ANSWER:
(a)
[tex]P_t=620\cdot(1-\frac{0.5}{100})^t[/tex](b) 561 thousand people
(c) During the year 2074
STEP-BY-STEP EXPLANATION:
(a) We can establish the formula to determine the population as follows:
[tex]P_t=620\cdot(1-\frac{0.5}{100})^t[/tex](b) To calculate the population, we know that the year 2030 would be t = 20 (2030-2010), therefore:
[tex]\begin{gathered} P_t=620\cdot(1-\frac{0.5}{100})^{20} \\ P_t=561 \end{gathered}[/tex](c) In this case, we know that the value of Pt is equal to 450, we replace and solve for t, like this:
[tex]\begin{gathered} 450=620\cdot(1-\frac{0.5}{100})^t \\ 0.995^t=\frac{450}{620} \\ t=\frac{\ln (0.726)}{\ln (0.995)} \\ t=63.9\cong64\rightarrow2010+64=2074 \end{gathered}[/tex]