Radioactive decay of the isotope $^{131}I $ follows first order kinetics. Its half-life time amounts to 8 days.
Calculate what fraction remains in a patient 24 days after the date of the absorption of this isotope.
- After the $8st$ day there remains $\frac{1}{2}$
- After the $16st$ day there remains $\frac{1}{2}$ of $\frac{1}{2}$ = $\frac{1}{4}$
- After the $24st$ day there remains $\frac{1}{2}$ of $\frac{1}{4}$ = $\frac{1}{8}$
