A demand loan of $4000.00 is repaid by payments of $1500.00 after two years, $1500.00 after four years, and a final payment after six years. Interest is 6% compounded quarterly for the first two years, 7% compounded annually for the next two years, and 7% compounded quarterly thereafter. What is the size of the final payment? The final payment is $nothing. (Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.