Answer :
We will have the following:
[tex]\begin{gathered} 1000000=500t^2\Rightarrow t^2=2000 \\ \\ \Rightarrow t=\sqrt{2000}\Rightarrow t=20\sqrt{5} \\ \\ \Rightarrow t=44.72135955... \end{gathered}[/tex]So, on day 44 it will reach 1 000 000.
We will have the following:
[tex]\begin{gathered} 1000000=500t^2\Rightarrow t^2=2000 \\ \\ \Rightarrow t=\sqrt{2000}\Rightarrow t=20\sqrt{5} \\ \\ \Rightarrow t=44.72135955... \end{gathered}[/tex]So, on day 44 it will reach 1 000 000.