I am having issues getting started. These are the first few. Once i understand these i should be fine. Thanks

How Much House Can You Afford?

Your annual gross (pre-tax) salary is $56,000. You can obtain a 30-year fixed rate mortgage at annual percentage rate (or APR) of 3.0%. You have $3,800 in other annual pre-tax income. You also have to pay $550 per month on an auto loan and student loans. What is the most expensive home you can buy under these circumstances?

1. How much monthly mortgage payment can you afford if it can be up to 28% of your gross (total) income? (Hint: This limit comes from the front-end ratio or mortgage to income ratio which is 28%. It means lenders will not allow you to take out a mortgage such that its monthly payment exceeds 28% of your gross monthly income. To find your gross income, be sure to include both your salary and other income.) (5 pts)
2. $1,395
3. $1,412
4. $1,427
5. $1,436

2. How much monthly mortgage payment can you afford if it can be up to 36% of your gross income when other long-term debt payments are included? (Hint: This limit comes from the back-end ratio or mortgage to income ratio which is 36%. It means lenders will not allow you to take out a mortgage such that its monthly payment when combined with payments towards other long-term debt obligations exceeds 36% of your gross monthly income. First find your gross annual income as you did in Problem 1. Then find 36% of your gross monthly income and finally subtract from that the payments required by other long-term debt obligations such as auto and student loans.) (5 pts)
3. $1,235
4. $1,244
5. $1,257
6. $1,268

3. What is the maximum amount you can borrow if you want to meet both the front-end and back-end ratio requirements? (Hint: Let c be the maximum monthly payment that will meet both the front-end and back-end ratios so c is the lesser of the two maximum allowed mortgage payments as computed in Problems 1 and 2. The maximum amount you can borrow is PV = (c / r) x (1- 1/(1+r)^t where r = monthly interest rate = APR / 12 and t = total number of monthly payments in a 30-year mortgage.) (5 pts)
4. $265,123
5. $274,586
6. $288,479
7. $295,064

4. Assuming that you are making a 20% down payment in order to avoid private mortgage insurance (or PMI), what is the price of the most expensive house you can afford to buy? (Hint: You already know the maximum amount you can borrow from Problem 3 which is equal 80% of the price of the most expensive house you can afford. In reality, this is an over-estimate of what you can afford because we neglected the effect of property taxes and homeowners insurance which can substantially increase your monthly mortgage payment.)
5. $349,753
6. $356,436
7. $368,829
8. $373,254

5. What is the amount of total interest paid over the entire 30-year term of the mortgage if you purchase the most expensive house you can afford as suggested by the previous problems? (Hint: Total interest paid = total number of monthly payments over 30 years x amount of monthly payment initial mortgage principal or amount borrowed.)
6. $150,892
7. $151,453
8. $152,776
9. $153,515