How much would \[tex]$200 invested at 4\% interest compounded monthly be worth after 8 years? Round your answer to the nearest cent.

\[ A(t) = P \left(1 + \frac{r}{n}\right)^{nt} \]

A. \$[/tex]205.40
B. \[tex]$275.28
C. \$[/tex]322.83
D. \$273.71



Answer :

To determine how much \[tex]$200 invested at an annual interest rate of 4%, compounded monthly, would be worth after 8 years, we can use the compound interest formula: \[ A(t) = P \left(1 + \frac{r}{n} \right)^{nt} \] where: - \( A(t) \) is the amount of money accumulated after n years, including interest. - \( P \) is the principal amount (the initial amount of money, which is \$[/tex]200 in this case).
- [tex]\( r \)[/tex] is the annual interest rate (decimal form, so 4% becomes 0.04).
- [tex]\( n \)[/tex] is the number of times that interest is compounded per year (monthly compounding means [tex]\( n = 12 \)[/tex]).
- [tex]\( t \)[/tex] is the number of years the money is invested for (8 years).

Let's break down the calculation step by step:

1. Principal, [tex]\( P \)[/tex]:
[tex]\[ P = 200 \][/tex]

2. Annual interest rate, [tex]\( r \)[/tex]:
[tex]\[ r = 0.04 \][/tex]

3. Compounding frequency, [tex]\( n \)[/tex]:
[tex]\[ n = 12 \][/tex]

4. Time in years, [tex]\( t \)[/tex]:
[tex]\[ t = 8 \][/tex]

Plug these values into the compound interest formula:

[tex]\[ A(t) = 200 \left(1 + \frac{0.04}{12}\right)^{12 \times 8} \][/tex]

Now let's simplify inside the parentheses first:

[tex]\[ 1 + \frac{0.04}{12} = 1 + 0.0033333 = 1.0033333 \][/tex]

Next, raise this to the power of [tex]\( 12 \times 8 \)[/tex]:

[tex]\[ (1.0033333)^{96} \][/tex]

Calculating this exponent:

[tex]\[ (1.0033333)^{96} \approx 1.376395 \][/tex]

Now multiply this with the principal amount:

[tex]\[ 200 \times 1.376395 \approx 275.2790238466248 \][/tex]

Finally, we round this amount to the nearest cent:

[tex]\[ \approx 275.28 \][/tex]

Thus, the value of the investment after 8 years is:

[tex]\[\$ 275.28\][/tex]

So the correct answer is (B) [tex]$\$[/tex] 275.28$.