Question

A high school student deposits there's summer job earnings $800 into a simple interest savings plan to 15% rate how much will a student have earned after 4 years

Answer 1

To calculate the amount earned with simple interest, you can use the formula:

\[
A = P(1 + rt)
\]

where:
- \(A\) is the amount of money accumulated after \(t\) years, including interest.
- \(P\) is the principal amount (the initial amount of money).
- \(r\) is the annual interest rate (in decimal).
- \(t\) is the time the money is invested or borrowed for, in years.

In this case:
- \(P = 800\)
- \(r = 0.15\) (15% expressed as a decimal)
- \(t = 4\)

Now plug the values into the formula:

\[
A = 800(1 + (0.15)(4))
\]

Calculating inside the parentheses first:

\[
0.15 \times 4 = 0.6
\]

So now we have:

\[
A = 800(1 + 0.6) = 800(1.6)
\]

Now multiply:

\[
A = 800 \times 1.6 = 1280
\]

The total amount after 4 years will be \(A = 1280\) dollars. To find out how much the student earned in interest, you subtract the principal from the total amount:

\[
\text{Interest earned} = A - P = 1280 - 800 = 480
\]

So, after 4 years, the student will have earned **$480** in interest.