Carolyn had her car towed when it broke down last week. It cost her $3 per mile to have it towed plus a flat fee of $50. The function for her cost was c(n)= 3x +50. If she had
the car towed 46 miles, how much did it cost?

I think you want the monthly payment.  (Equation is attached).

Monthly Payment equals 21.10

If you are looking for the total interest paid then we need the

Total Loan Cost Formula. (attached)

The monthly loan rate is .06 / 12 = .005 and

number of payments = 12 months * 15 years = 180

Total Cost = .005 * 2,500 * 180 / 1 -(1.005)^-180

= 3,797.36

Total Cost  3,797.36

Minus Principal 2,500

Equals total interest paid = 1,297.36

Step-by-step explanation: