You want to buy a second-hand car today that costs $28,000,000 and you agree with the seller the following terms: You will pay the owner an initial fee of 40%. The balance will be paid with a payment of $6,000,000 in 8 months and a final payment in 16 months (as of today).

a. If the interest rate agreed with the seller is 1.55% per month, how much is the final payment?
b. Now suppose that the interest rate agreed with the seller is 15% per year, how much
is the final payment?

Please provide the procedure and explanations.