Final answer:
To calculate the amount of money your parents will have at the end of four years, we need to consider the contributions they made, the year-end vacations, and the interest rate. Your parents will have approximately $67,393.55 at the end of four years to help you with your graduate school.
Step-by-step explanation:
To calculate the amount of money your parents will have at the end of four years, we need to consider the contributions they made, the year-end vacations, and the interest rate.
First, let's calculate the future value of the $21,000 that your parents gave to Courtney to help her start her nail salon. Using the formula for compound interest, the future value is:
Future Value = Present Value × (1 + Interest Rate)^Number of Periods
Future Value = $21,000 × (1 + 7%)^4 = $28,074.87
Next, let's calculate the future value of the year-end vacations. The future value of each vacation is calculated using the same formula:
Future Value = Yearly Cost × (1 + Interest Rate)^Number of Years
Future Value = $8,000 × (1 + 7%)^4 = $9,406.57
To find out the total amount your parents will have at the end of four years, we add the future value of Courtney's gift and the future values of the vacations:
Total Future Value = $28,074.87 + ($9,406.57 × 4) = $67,393.55
Therefore, your parents will have approximately $67,393.55 at the end of four years to help you with your graduate school.