I need some help on Corporate Finance please, much appreciated!

Vito Scaletta just bought his dream car, 2014 Aston Martin DB9 that cost $208,700. He paid $35,000 down and financed the balance over 84 months at 6.25% p.a. (Assume that Vito makes all required payments on time). 28. What is the monthly payment on Vito's loan? 29. What will the balance on Vito's loan be at the end of the fourth year (that is, immediately after Vito makes his 48th payment on the loan)? 30. What is the total amount of interest that Vito will pay over the entire term of the loan (that is, the total amount of interest that is paid on payments 1 through 84)? 31. Today is your 30th birthday and you have a dream of retiring on your 65th birthday. You want to put aside however much is necessary on your 31st through 65th birthdays (35 annual payments) to have enough to retire. You've estimated that you will live until you are 90 and you want the first withdrawal to occur on your 66th birthday, with the last payment occurring on your 90th birthday. You think that you will need $150,000 per year to spend during retirement. You estimate constant interest rates of 11.25%. Assuming that you currently have $7,500 deposited in your retirement account, how much must you put aside each year in order to have sufficient money to retire at age 65? 32. John Keene recently invested $5,000 in a project that is promising to return 6.5 percent per year. The cash flows are expected to be as follows: End of Cash Year Flow 1 $1000 2 950 3 875 4 ??? 5 850 Note that the 4th year cash flow is unknown. Assuming the present value of this cash flow stream is $5,000 (that is, CF0 = -5000), what is the missing cash flow value (that is, what is the cash flow at the end of the 4th year)? 33. You have a $25,000 balance on your credit card. You plan to make monthly payments of $450 until the balance is paid off. The interest rate on your credit card is 17.5% p.a., compounded monthly. A letter in the mail informs you that you are approved for a new credit card and balance transfers are subject to a 9.5% p.a., compounded monthly. How many months sooner will you pay off your bill