In the beginning of 2000,Ken borrowed $40000 from a bank at an interest rate of 16% p.a. compounded quarterly.
(a) How much compound interest did Ken owe the bank in the beginning of 2004?
(b) If Ken repaid $10000 at the end of each year,how much did he owe the bank in the beginning of 2004?
(Give your answer correct to nearest $1)