Answer:
He would have to invest $80,412.
Explanation:
Compound interest:
The compound interest formula is given by:
![A(t) = P(1 + (r)/(n))^(nt)](https://img.qammunity.org/2022/formulas/mathematics/college/jij6dzyugcwh9r2wcu470rclc9mroo9e6g.png)
Where A(t) is the amount of money after t years, P is the principal(the initial sum of money), r is the interest rate(as a decimal value), n is the number of times that interest is compounded per year and t is the time in years for which the money is invested or borrowed.
Assuming an interest rate of 3,43% compounded quarterly.
This means that
![r = 0.0343, n = 4](https://img.qammunity.org/2022/formulas/mathematics/college/lpp25a57zq6qz31gmuf8f584li4h5m0vq9.png)
How much would he have to invest to have $148,700 after 18 years?
This is P for which
. So
![A(t) = P(1 + (r)/(n))^(nt)](https://img.qammunity.org/2022/formulas/mathematics/college/jij6dzyugcwh9r2wcu470rclc9mroo9e6g.png)
![148700 = P(1 + (0.0343)/(4))^(72)](https://img.qammunity.org/2022/formulas/mathematics/college/9wprpf3mlh3rn911b72q3f5dzeeopqeolk.png)
![P = (148700)/((1 + (0.0343)/(4))^(72))](https://img.qammunity.org/2022/formulas/mathematics/college/z9xkahiz5irlx0br5dvnscfuggealcfzyq.png)
![P = 80412](https://img.qammunity.org/2022/formulas/mathematics/college/eudbdziga579qrwy1isado5p5zxi3vu5g6.png)
He would have to invest $80,412.