Answer:
Approximately 76.5 mg.
Step-by-step explanation:
Given,
The initial quantity of the Bismuth-210, P = 233 mg,
Also, the rate of decay per day, r = 13 %
Thus, the quantity of the Bismuth-210 after 8 days would be,
[tex]A=P(1-\frac{r}{100})^8[/tex]
[tex]=233(1-\frac{13}{100})^8[/tex]
[tex]=233(1-0.13)^8[/tex]
[tex]=233(0.87)^8[/tex]
[tex]=76.4733194697[/tex]
[tex]\approx 76.5\text{ mg}[/tex]