You want the unit cost __per__ student.
That means divide the cost by the number of students.
$65.50/12 = $5.46
Answer: C. $5.46
this question is non linear
Sales commission : 5% of 900,000....0.05(900,000) = 45,000
managers salary : 96,000
ads : 80,000
shipping : 2% of 900,000...0.02(900,000) = 18,000
misc. 2100 + 0.5(0.01(900,000)) = 2100 + 4500 = 6600
total selling expenses :
45,000 + 96,000 + 80,000 + 18,000 + 6600 = 245,600 <==