Showing your work on paper, can someone help me with this.

Problem 5. A borrower takes out a 15-year loan at an interest rate of 8.40 0 per year, compounded monthly. The loan is paid off in equal monthly payments (due at the end of each month). Each payment is made up of an interest payment and a payment against the principal. (a) What percentage of the first month's payment is interest payment? (b) In which month's payment does the payment against the principal first become more than the interest payment?