Answer:
The time it will take for this investment is;
[tex]t=19.50\text{ years}[/tex]Explanation:
Given that the initial investment was $6,000.
[tex]P=6,000[/tex]And the final amount is $27,696.
[tex]F=27,696[/tex]at an annual rate of 8%, compounded semiannually;
[tex]\begin{gathered} r=0.08 \\ n=2 \end{gathered}[/tex]Recall that the formula for calculating compound interest can be written as;
[tex]F=P(1+\frac{r}{n})^{nt}[/tex]Where t is the time of investment.
Making t the subject of the formula;
[tex]\begin{gathered} F=P(1+\frac{r}{n})^{nt} \\ \frac{F}{P}=(1+\frac{r}{n})^{nt} \\ \ln (\frac{F}{P})=nt\ln (1+\frac{r}{n}) \\ t=\frac{\ln(\frac{F}{P})}{n\ln(1+\frac{r}{n})} \end{gathered}[/tex]Substituting the given values;
[tex]\begin{gathered} t=\frac{\ln(\frac{F}{P})}{n\ln(1+\frac{r}{n})}=\frac{\ln (\frac{27696}{6000})}{2\ln (1+\frac{0.08}{2})} \\ t=19.50\text{ years} \end{gathered}[/tex]Therefore, the time it will take for this investment is;
[tex]t=19.50\text{ years}[/tex]