Final answer:
Matt paid $554 in interest on a car loan of $7100 over four years, which is the difference between the total amount paid and the original loan amount.
Step-by-step explanation:
Matt took out a car loan for $7100 and after four years, he paid a total of $7654. To calculate the total interest paid on the loan, we subtract the original loan amount from the total amount paid over the four years:
- Total amount paid: $7654
- Original loan amount: $7100
- Total interest paid: $7654 - $7100 = $554
Therefore, Matt paid $554 in interest over the lifespan of his four-year car loan.