15 credits & $650.25 per credit & $535.85 scholarship for each credit = (650.25-535.85)×15 = 114.4×15= $1716
He will need to pay $1,716 in tuition next semester
2nd Part-> 15 credits & $675 per credit & $485.15 scholarship for each credit = (675-485.15)×15 = 189.85 × 15 = $2847.75
$2847.75 - $1716 = $1131.75
He will need to pay $1131.75 more for next semester