Vince deposited $4,000 in a savings account with simple interest. Two years later, the account held $5,040. What was the interest rate?

Respuesta :

Answer: The interest rate is 13%.

Step-by-step explanation:

To find the interest rate, we need to use the simple interest formula:

\[ I = P \times r \times t \]

Where:
- \( I \) is the interest,
- \( P \) is the principal amount (the initial amount of money),
- \( r \) is the interest rate (as a decimal),
- \( t \) is the time the money is invested or borrowed for, in years.

From the information provided, we know that Vince deposited $4,000 and after two years the account held $5,040. So, the interest \( I \) earned can be calculated by:

\[ I = Total \, Amount - Principal \, Amount \]
\[ I = 5,040 - 4,000 \]
\[ I = 1,040 \]

We know the principal amount \( P \) is $4,000 and the time \( t \) is 2 years. Now we can plug these values into the formula and solve for the rate \( r \).

\[ 1,040 = 4,000 \times r \times 2 \]

Now, let's solve for \( r \):

\[ r = \frac{1,040}{(4,000 \times 2)} \]
\[ r = \frac{1,040}{8,000} \]
\[ r = 0.13 \]

To express the interest rate as a percentage, we multiply the decimal by 100:

\[ r = 0.13 \times 100 \]
\[ r = 13\% \]

Therefore, the interest rate is 13%.
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