Charles is going to purchase a new car that has a list price of $25,995. he is planning on trading in his good condition 2008 dodge viper and financing the rest of the cost over three years, paying monthly. his finance plan has in an interest rate of 13.75%, compounded monthly. charles will also be responsible for 7.6% sales tax a $1,372 vehicle registration fee and $169 documentation fee. if the dealer gives charles 80% of the listed trade in price on his car, once the financing is paid off, what percent of the total amount paid will the interest be?