there are both part a and part b questions.. can you help me solve those?

A loan of 6,391 is subject to a flat rate of interest of 20% p.a. a) Calculate the level monthly repayments, made in arrears.[2] b) If the term of the repayments is 15 months, deduce the APR applying. [2] An investor receives an annual annuity for 14 years. Payments increase by 6% p.a. compound. The first payment is 591 paid on 1st January 2000. Find the accumulated value of the entire payments at 31st December 2019 if the payments earn interest of 4% per half year