Final answer:
To determine the monthly savings by choosing the dealership's 5.9% APR over the bank's 7.9% APR for a $19,500 car financed over five years, apply the installment loan formula to each APR and then calculate the difference between the two resulting monthly payments.
Step-by-step explanation:
Joslyn is considering financing options for a $19,500 car over a five-year period and wants to know how much money she will save each month by choosing financing through the dealership at a 5.9% APR instead of her bank's 7.9% APR.
To calculate the monthly payment for each APR, we can use the formula for an installment loan, which is:
M = P [ i(1 + i)^n ] / [ (1 + i)^n - 1]
where:
- M is the monthly payment
- P is the principal amount ($19,500)
- i is the monthly interest rate (annual rate / 12)
- n is the number of payments (5 years x 12 months/year)
For the bank's 7.9% APR:
i = 7.9% / 12 = 0.007583
n = 5 x 12 = 60
For the dealership's 5.9% APR:
i = 5.9% / 12 = 0.004916
Calculating separately each monthly payment and then finding the difference will give us the amount saved per month by choosing the dealership's offer over the bank's.