Solution:
From the question, we use the population decay formula expressed as
[tex]\begin{gathered} P(t)=P(1-r)^t \\ where \\ P\Rightarrow initial\text{ population} \\ r\Rightarrow decay\text{ rate} \\ t\Rightarrow time \\ P(t)\Rightarrow population\text{ at time t} \end{gathered}[/tex]Given that:
[tex]\begin{gathered} P=158000 \\ r=8\%=\frac{8}{100}=0.08 \\ t=5 \end{gathered}[/tex]By substituting these values into the population decay formula, we have
[tex]\begin{gathered} P(t)=158000(1-0.08)^5 \\ =104134.88066 \end{gathered}[/tex]Hence, the population in 5 years will be
[tex]104134.88066[/tex]