The mass decay rate is of the form
[tex]m(t) = m_{0} e^{-kt}[/tex]
where
m₀ = 3000 g,the initial mass
k = the decay constant
t = time, years.
Because the half-life is 30 years, therefore
[tex]e^{-30k} = \frac{1}{2} \\\ -30k = ln(0.5) \\ k = \frac{ln(0.5)}{-30} =0.0231[/tex]
After 60 years, the mass remaining is
[tex]m = 3000 e^{-0.0231*60} = 750 \, g[/tex]
Answer: 750 g
