Okay, here we have this:
Considering the provided information, we are going to calculate the total cost of one CD, so we obtain the following:
First we will calculate the total cost of the 20 CDs by adding the total taxes and shipping that had to be paid:
Total Cost=$214.60+$15.00
Total Cost=$229.60
Unitary Cost=Total cost / Quantity
Unitary Cost=$229.60/20
Unitary Cost=$11.48
Finally we obtain that the cost of one CD is $11.48