There is a problem, a great god to solve! A research on the current bank and small lump deposit savings rates of different period, calculate the principal and interest of a certain period of maturity and the interest and principal and, The current term interest rate as lump sum reference: (%) Half a year, 2.00 A: 2.5 Two years: 3.00 Three years: 3.5 Four years: 4.00 Five years: 4.5