The total cost of the car = down payment
+ total installments
For total installments:
The first step is to find out the number of months Tom will pay:
5.5 years x 12 months in a year = 66 months
If he pays $325 per month, he will pay $325 x 66 = $21,450 in installments.
Add this to his down payment for the total cost of the car:
$3,800 + $21,450 = $25,250 (the total cost of the car)