Without using excel

a) A loan of $5,000 is to be repaid in equal monthly payments over the next 2 years. Determine the payment amount if interest is charged at a nominal annual rate of 15% compounded semiannually.

b) Net receipts from a continuously producing oil well add up to $120,000 over 1 year. What is the present amount of the well if it maintains steady output until it runs dry in 8 years if r = 10% compounded continuously?