a)
Every 63 years, the amount of titanium halves.
441 years later means how many halving?
441/63 = 7 halving
We start off with 1000 and do 7 halving to get the amount of Titanium-44 after 441 years.
[tex]\begin{gathered} 1000(\frac{1}{2})^7 \\ =7.8125 \end{gathered}[/tex]after 441 years, the amount of titanium remaining would be 7.8125 kg
b)
Let's find the point where the remaining titanium would be 1 kg.
That would be:
[tex]1=1000(\frac{1}{2})^t[/tex]t is the time we are looking for. We can solve this using Ln(natural log):
[tex]\begin{gathered} 1=1000(\frac{1}{2})^t \\ 0.001=\frac{1}{2}^t \\ ln(0.001)=\ln (\frac{1}{2}^t) \\ \\ t=\frac{\ln (0.001)}{\ln (\frac{1}{2})} \\ t=9.965 \end{gathered}[/tex]There is basically 9.965 halving. That would make the years approximately:
9.965 * 63 (half life) = 627.795 years (approx)