A loan of $25,000 with a 4.5% effective interest rate is being paid back with yearly payments of $2500 until a final, irregular payment.

(a) If the final, irregular payment is to be a drop payment, find the total number of payments and the amount of the final payment.

(b) If the final, irregular payment is to be a balloon payment, find the total number of payments and the amount of the final payment.