If the Koslow family makes only the minimum payment for 11 months, they would have paid a total of $68 x 11 = $748.
To determine how much they would have to pay in the 12th month to pay off the balance, we need to subtract the total amount paid in the first 11 months from the original purchase amount:
$6,283 - $748 = $5,535
Therefore, the Koslow family would have to pay $5,535 in the 12th month to pay off the balance in full within twelve months.