Use the compound interest formulas, [tex]A=P\left(1+\frac{r}{n}\right)^{nt}[/tex] and [tex]A=Pe^{rt}[/tex], to solve the following problem.

Suppose that [tex]$\$[/tex]14,000[tex]$ is to be invested. Which investment yields the greater return over 2 years: $[/tex]12\%[tex]$ compounded monthly or $[/tex]11.92\%[tex]$ compounded continuously?

Choose the correct answer below:

A. $[/tex]12\%[tex]$ compounded monthly
B. $[/tex]11.92\%$ compounded continuously



Answer :

To determine which investment yields the greater return over 2 years, we'll use the compound interest formulas for both situations given:

1. Compounded monthly:
The formula for compound interest when interest is compounded periodically is:
[tex]\[ A = P \left(1 + \frac{r}{n}\right)^{nt} \][/tex]
where:
- [tex]\(A\)[/tex] is the amount of money accumulated after n years, including interest.
- [tex]\(P\)[/tex] is the principal amount (the initial amount of money, which is [tex]$14,000). - \(r\) is the annual interest rate (in decimal form, so 12% is 0.12). - \(n\) is the number of times that interest is compounded per unit time (12 for monthly compounding). - \(t\) is the time the money is invested for in years (2 years). Plugging in the known values: \[ A_{\text{monthly}} = 14000 \left(1 + \frac{0.12}{12}\right)^{12 \times 2} \] Upon calculating this, we find that: \[ A_{\text{monthly}} \approx 17776.29 \] 2. Compounded continuously: The formula for compound interest when interest is compounded continuously is: \[ A = P e^{rt} \] where: - \(A\) is the amount of money accumulated after n years, including interest. - \(P\) is the principal amount (the initial amount of money, which is $[/tex]14,000).
- [tex]\(r\)[/tex] is the annual interest rate (in decimal form, so 11.92% is 0.1192).
- [tex]\(t\)[/tex] is the time the money is invested for in years (2 years).
- [tex]\(e\)[/tex] is the base of the natural logarithm, approximately equal to 2.71828.

Plugging in the known values:
[tex]\[ A_{\text{continuous}} = 14000 \cdot e^{0.1192 \times 2} \][/tex]

Upon calculating this, we find that:
[tex]\[ A_{\text{continuous}} \approx 17769.03 \][/tex]

Comparing the two amounts:
- [tex]\(\$ 17,776.29\)[/tex] for the investment compounded monthly at 12%.
- [tex]\(\$ 17,769.03\)[/tex] for the investment compounded continuously at 11.92%.

The investment that yields the greater return over 2 years is the 12% compounded monthly.

Thus, the correct answer is:
[tex]\[ \boxed{\text{12% compounded monthly}} \][/tex]