4. My son recently had his 5th car accident in the last year or so and needs a new car. He has $3,000 saved for a down payment and can get a 3-year loan for 8% APR compounded monthly. If he buys a $10,000 car, then what will be his monthly car payment? 5. We would all like to retire someday. Assume that you will make annual retirement contributions for the next 30 years at the end of each year (first payment to be made one year from today). If you can earn 10% APR, then how much do you need to contribute each year to have $3,000,000 in your retirement account? How much would your first payment need to be your annual payments increase by 5% each year? 6. I expect to be retired for about 18 years (216 months). I expect to earn 6% APR compounded monthly (after-tax) on my investments during my retirement years and I also expect inflation to average about 2.4% annually (compounded monthly). How much do I need to have saved to be able to spend the equivalent of $10,000 per month during each month of my retirement (note that the $10,000 will increase each month to keep my purchasing power at $10,000 in today's dollars)