Present value with periodic rates.

Sam Hinds, a local dentist, is going to remodel the dental reception area and add two new workstations. He has contacted A-Dec, and the new equipment and cabinetry will cost $20,000. The purchase will be financed with an interest rate of 7.5% loan over 8 years. What will Sam have to pay for this equipment if the loan calls for quarterly payments (4 per year) and weekly payments (52 per year)? Compare the annual cash outflows of the two payments. Why does the weekly payment plan have less total cash outflow each year?