Given:
Principal amount $30000.
Rate = 6%
Number of years = 18.
The amount after 18 years is calculated as,
[tex]\begin{gathered} A=P(1+\frac{R}{100})^{nt} \\ P=30000 \\ R=6 \\ n=2\text{ ( Compunded semiannually)} \\ t=18 \\ A=30000(1+\frac{6}{2\times100})^{2\times18} \\ A=30000(1.03)^{36} \\ A=86948.35 \end{gathered}[/tex]Answer: The total amount is $86948.35