with clear manual solution, thank you!

A. Merlin Mermer is a car salesman earning commission at a rate of 23%. He closed a deal for a car whose balance of P650,000 will paid monthly in 3 years at an interest rate of 6%. Compute the total commission Merlin Mermer will earn once total payment is completed. B. Annie Mae Karton works as a sales agent for a certain company. She was able to sell a product worth P42,000 at an interest of 4% to be paid in 4 equal monthly payments. For the 1st term, she will earn 5.5% in commission which will decrease by 0.5% next term and for each of the succeeding outstanding balances. Compute Annie Mae' commission for each of the term and in total