Follow the steps above and find c, the total of the payments, and the monthly payment. Choose the right answers. Tom Slick buys a set of tires for his car. The price, including tax, is $950.00. Tom finances the tires over 12 months after making a $50 down payment. The true annual interest rate is 18%. What are his monthly payments (principal plus interest)? To the nearest penny, c = $. Total of payments = amount financed + c = $. Total of payments ÷ number of payments = monthly payment = $.