To calculate the total amount Beth would have to repay Julie using the simple interest formula, we can use the following formula for simple interest:

$I = P \times r \times t$

Where:

• $I$ is the interest,
• $P$ is the principal (the amount borrowed),
• $r$ is the nominal interest rate per period (expressed as a decimal),
• $t$ is the time the money is borrowed for (in years).

Given that:

• The principal $P = 500$,
• The annual nominal interest rate $r = 9\% = 0.09$,
• The time $t = 1$ year.

First, calculate the interest:

$I = 500 \times 0.09 \times 1 = 45$

So, the interest is $45.

To find the total amount to be repaid, we add the interest to the principal:

$\text{Total amount} = P + I = 500 + 45 = 545$

Thus, the total amount Beth would have to repay at the end of the year is $545.00.

Would you like further details or clarification on the steps?

Here are five related questions you might find interesting:

1. How do you calculate compound interest and compare it with simple interest?
2. What would happen to the total repayment if the interest rate was higher?
3. How can semi-annual compounding affect the overall loan repayment?
4. What is the formula for calculating monthly payments on a loan?
5. How does the length of the loan affect the total interest paid?

Tip: When dealing with interest, always confirm whether the rate is annual or semi-annual, and adjust your calculations accordingly!