Answer
(a) $5.08$ percent
(b) $46754.26$ dollars
Work Step by Step
(a) After 30 days, $t=30$.
Substitute $t$ into the formula given to estimate the expected percent of radioactive material:
$y=100(2.7)^{-0.1 \times 30} \approx 5.08$.
b) Use the formula:
$A = P(1+\frac{r}{n})^{nt}$
Substitute known values from the problem:
$A = 23000(1+\frac{0.12}{4})^{24} \approx 46754.26$.