2. (1 point each) Sarek has a 15-year mortgage with level monthly payments. The amount of principal in his 43 rd payment is $685.01, and the amount of principal in his 68 th payment is $766.38. (a) Find the amount of principal in his 112 th payment. (b) Find the original amount of the loan. (c) Find the outstanding loan balance at the end of 10 years, just after the payment that day is made