You wish to borrow $20,000 from the bank. The applicable rate is 8% p.a. compounded quarterly. You will repay by making a total of 4 cash repayments. The payments will be in exactly one, two, three and four years' time. The second payment will be twice the amount of the first payment. The third payment will be twice the second payment, and the fourth payment will be twice the third payment. Calculate the amounts of the four payments.