Final answer:
Frances will earn $52.50 in interest at the end of 5 years.
Step-by-step explanation:
To calculate the interest earned, we can use the formula for simple interest: I = PRT, where I is the interest earned, P is the principal amount, R is the interest rate, and T is the time in years. In this case, Frances lent her sister $350 at an annual rate of 3% for 5 years. Plugging in the values, we have I = 350 * 0.03 * 5 = $52.50. Therefore, Frances will earn $52.50 in interest at the end of 5 years.