I need help on C......

Step-by-step explanation:
[tex]B=100e^{0.592t}[/tex]
c) To solve for t, take the natural logarithm of the above equation:
[tex]\dfrac{B}{100}=e^{0.592t}[/tex]
[tex]\Rightarrow \ln \left(\dfrac{B}{100} \right) = \ln e^{(0.592t)}=(0.592t)\ln e[/tex]
Recall that [tex]\ln e = 1[/tex] so we can rewrite the equation above as
[tex]0.592t = \ln \left(\dfrac{B}{100} \right)[/tex]
Finally, solving for t, we get
[tex]t = \frac{1}{0.592} \ln \left(\dfrac{B}{100} \right)[/tex]