A variable rate demand loan showed an initial balance of

$12,000.00,

payments of

$5500.00

after six months,

$5500.00

after 21 months, and a final payment after

five

years. Interest was

9%

compounded

quarterly

for the first 21 months and

8.6%

compounded

monthly

for the remaining time. What was the size of the final payment?