Discount Thank You Notes Please Help About Discounting Notes Problems!?

Please help about discounting notes problems!? - discount thank you notes

Ok, I can not imagine what to evaluate this issue, because I did not get a good formula for deriving the rate. Here lies the problem:
Joey signed a note discount of U.S. $ 100,000 in the bank. If the product is $ 143,500, and the duration was 8 months, as the interest rate was in advance? Is this the correct formula to use?
P = F (1-DT)
Another problem of payment:
A note on simple interest on $ 65,000, signed May 15, 2007 and September 14, 2007. Find the charge if the remaining life is $ 68,350.
If you know the answer, please briefly explain or show your solution and the formula he used. That's my job. Well, I thank you in advance.