CNBC reported that one in five consumers who purchase bitcoin do so using their credit card. Melissa Gamez purchased a used RV with 20,500 miles for $48,400. Originally the RV sold for $77,500 with a residual value of $21,500. After subtracting the residual value, depreciation allowance per mile was $0.94 How much was Melissa's purchase price over or below the book value? Note: Input the amount as positive value