dont need the explanation just the formula for excel:)

The following data is entered into an Excel worksheet for alone-time investment: Annual Rate of Return, cell E1, 5.5% Years Attending College, cell E2, 4 Years Total Cost per Year, cell E3, $20,000 Write a function that will calculate the amount of money that needs to be invested today in order to provide funds for 4 years of college. Assume payments are made at the beginning of each year. Write the function as if you were entering it into an Excel worksheet