The interest of a compound interest investment or loan can be computed with the formula I = A P (where A is given below) . The end amount of a compound interest investment or loan can be computed with the formula A = P ( 1 + r n ) n t . Use these formulas to evaluate the amounts indicated below. Let P = $ 4 , 200 , r = 12.3 % , n = 12 , and t = 3 years. Determine the interest, I , at the end of 3 years. Interest = $ dollars