Please show work or show work in excel!

1.You can lease a truck for 4 years at a cost of 30k annually.you can also buy a truck for 80k with annual maintenance expenses of 10k. you will sell the truck at the end of year 4 for 20k. what is the better option if the discount rate is 10%??

2.10 year bond just issued pays 12% semiannual coupon with par value 1000. the bond can be called 4 years at call price of 1060 and the bond sells for 1100.bonds current yield?bonds yield to call?

3.Thinking about retirement they decide to put aside 3k each year in a saving plan that earns 8% interest. In 5 years they will receive a gift of 10k that also can be invested. How much money will they have accumulated 30 years from now?

If the goal was to retire with 800k of saving, how much extra do they need to save every year?

4.what will be the monthly payment if you borrow with a 100k 15-year mortgage at an interest rate of 1% per month? How much of the first payment is interest? How much is principal amortization?