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