A young couple buying their first home borrow $80,000 for 30 years at 7.4%, compounded monthly, and make payments of $553.90. After 4 years, they are able to make a one-time payment of $2,000 along with their 48th payment.

(a) Find the unpaid balance immediately after they pay the extra $2,000 and their 48th payment. (Round your answer to the nearest cent.) $ (b) How many regular payments of $553.90 will amortize the unpaid balance from part (a)? Give the answer to one decimal point. payments