In order to determine how much is the amount the woman should invest, use the following formula for the amount of money earnt with compound interest:
![A=P(1+(r)/(n))^(nt)](https://img.qammunity.org/2023/formulas/mathematics/high-school/39foo2gerf9tf1ffk32zwshrn339mz02kv.png)
where,
A: amount obtained after t years = $45,000
P: principal investment = ?
r: percentage rate = 6% = 0.036
n: times at year = 2 (semiannually)
t: time = 15 years
Replace the previous values of the parameters and then solve for P, as follow:
![\begin{gathered} 45,000=P(1+(0.06)/(2))^(2\cdot15) \\ 45,000=P(2.43) \\ P=(45,000)/(2.43)=18,539.40 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7os7138jjn6pepxmauxfntt9nif7csl9zq.png)
Hence, the woman should invest approximately $18,539.40