Rania takes out a loan for $50,000 which she will repay with 10 annual payments of $K (at the end of each year for the next 10 years). a) Using the Prospective Formula for the outstanding balance TH OB = - k=t+1 (where v is the annual discount factor 1/(1+i)), together with the formula OB = OB-1 - PR prove (for all t, 1