The equation for the amount left after t years if half life is
[tex]t_{\frac{1}{2}}[/tex]and initial amount is A is,
[tex]A^{\prime}=A(\frac{1}{2})^{\frac{t_{}}{t_{\frac{1}{2}}}}[/tex]Determine the amount left after 450 years.
[tex]\begin{gathered} A=379200\times(\frac{1}{2})^{\frac{450}{90}} \\ =379200\times(\frac{1}{2})^5 \\ =11850 \end{gathered}[/tex]Thus amount of samarium left after 450 years is 11850 grams.