Question

Julieta invests money in an account paying a simple interest of 7, percent7% per year. If mm represents the amount of money she invests, which expression represents her balance after a year, assuming she makes no additional withdrawals or deposits?

Answer 1

To calculate the balance after one year with a simple interest rate of 7%, you can use the formula for simple interest:

\[
\text{Total Balance} = \text{Principal} + \text{Interest}
\]

Where the interest is calculated using the formula:

\[
\text{Interest} = \text{Principal} \times \text{Rate} \times \text{Time}
\]

In this case:

- \( \text{Principal} = mm \) (the initial amount invested)
- \( \text{Rate} = 0.07 \) (7% expressed as a decimal)
- \( \text{Time} = 1 \) year

Now, substituting these values into the interest formula:

\[
\text{Interest} = mm \times 0.07 \times 1 = 0.07mm
\]

Now, substituting this back into the total balance formula:

\[
\text{Total Balance} = mm + 0.07mm
\]

Combining like terms gives:

\[
\text{Total Balance} = 1mm + 0.07mm = 1.07mm
\]

Thus, the expression that represents Julieta's balance after a year is:

\[
1.07mm
\]