Please Answer C1 to C3 with process

Jim and Pam Halpert wish to buy a new house in Scranton Pennsylvania. The listing price is $650,000 and they plan to put 20% as down payment. New Rochelle Savings and Loan will lend them the remainder at a 4.8% fixed APR for 30 years, with monthly payments to begin in one month. For simplicity, let's ignore closing costs and taxes when solving this question. a). How much will their monthly payments be? b). New Rochelle Savings and Loan also offers them an option for a 15 year loan with 4.2% APR. How much extra must they pay in each month if they chose the 15 year loan over the 30 year loan? cl). Suppose they eventually chose the 30 year plan. Now, fast-forward 12 years. They have been making monthly mortgage payment (the number you computed in part a) on time in the last 12 years. What is the remaining balance on their loan now? c2). (Continue from c1) Jim and Pam' rich friend, agro-tourism tycoon Dwight Schrute, gifts them a lump sum of $80,000 to pay down their remaining mortgage balance. After the help from this generous friend, what is their remaining balance? c3). (Continue from c2) After the help form this generous friend, Pam and Jim decide to continue to pay the same monthly payment as before (the number you computed in part a). How many months left for them to be debt-free? 17000