Question

A high school student deposits their summer job earnings of $800 into a simple interest savings plan with a 15 rate. How much will the student have earned after 4 years?

Answer 1

To calculate the interest earned on a simple interest savings plan, you can use the formula:

\[
\text{Interest} = P \times r \times t
\]

where:
- \( P \) is the principal amount (initial deposit),
- \( r \) is the annual interest rate (in decimal form),
- \( t \) is the time in years.

In this case:
- \( P = 800 \) (the initial deposit),
- \( r = 15\% = 0.15 \) (converting the percentage to decimal),
- \( t = 4 \) (the number of years).

Now, substitute the values into the formula:

\[
\text{Interest} = 800 \times 0.15 \times 4
\]

Calculating it step by step:

1. Calculate \( 800 \times 0.15 \):
\[
800 \times 0.15 = 120
\]

2. Now multiply by \( 4 \):
\[
120 \times 4 = 480
\]

So the total interest earned after 4 years is \( 480 \).

To find out how much the student will have in total after 4 years, we add the interest to the principal:

\[
\text{Total Amount} = P + \text{Interest} = 800 + 480 = 1280
\]

Thus, the student will earn a total of **$480** in interest and have **$1280** in the account after 4 years.