[15] A loan of $ 20000 is to be amortized with equal semi-annual payments over a period of 7 years at i(2) = 5%. (a) [5] Determine the amount of the regular payments if they are rounded up to the nearest cent. (b) [5] Compute the concluding payment in case of (a) if it is rounded to the nearest cent. (c) [5] Compute the concluding payment if the regular payments are rounded to the nearest cent. (The concluding payment is also rounded to the nearest cent.)