A business borrowed $66,000 to be repaid in seven equal annual installments. The promissory note amortization table is as follows:

Principal Interest Payment $66,000 1 14,462 7,920 6,542 59,458 2 14,462 7,135 7,327 52,131 3 14,462 6,256 8,206 43,925 4 14,462 5,271 9,191 34,735 5 14,462 4,168 10,294 24,441 6 14,462 2,933 11,529 12,912 7 14,462 1,549 12,912 (0)

a. What is the annual interest rate on this note?

b. Assume the annual payment is $10,000 (all other variables equal), how much will the principal balance due at the end of the seventh year