Solution
- We are required to find the compound interest on a $1200 invested in a retirement account if it is compounded annually at 8% interest for 2 years.
- In order to find the compounded interest, we use the formula:
![\begin{gathered} A-P=I \\ \text{where,} \\ A=\text{ Amount compounded after n years} \\ P=\text{ Principal or Initial Amount} \\ I=\text{ Compounded interest} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5ltt5sfu1q8wr1gdbyckmln8mpyldseaks.png)
- But before we can use the above formula, we need to first calculate the Amount compounded. This can be gotten using the formula below:
![\begin{gathered} A=P(1+(r)/(n))^(nt) \\ \\ \text{where,} \\ n=\text{ The number of times the interest in compounded per year} \\ t=\text{ Number of years} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/cmizi5bbxjb78hv8flcx7sw4zv5w4uxyym.png)
- Thus, we can proceed to solve the question by first finding the Amount compounded over the 2 years and then going on to calculate the compound interest.
Compounded Amount:
We can find the compounded amount as follows:
![\begin{gathered} A=P(1+(r)/(n))^(nt) \\ \\ A=1200(1+(8)/(100*1))^(2*1) \\ \\ A=1200(1+(8)/(100))^2 \\ \\ A=1399.68 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5zdin0ro8yedto974npo6byyhxy3sii0as.png)
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Compounded interest
![\begin{gathered} I=A-P \\ I=1399.68-1200 \\ \\ \therefore I=199.68 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/omvbci6k4tqdg2f65mxf3za9zi4h23eq3s.png)
Final Answer
The interest is $199.68