Answer:
$111.59
Explanation:
The total amount of the purchase was the cost of the computer plus the sales tax:
$1,257*1,06= $1,332.42
Now, to determine the interest that they will have to pay, you have to consider that the interest rate is 16,75% APR that is the annual percentage rate but as only 6 month have passed, the interest rate at this point that they have to pay is 8.375%:
$1,332.42*8.375%= $111.59
The interest that they will be charged is $111.59