There are 3 Tejano CDs, but we have 4+1+2+3=10 CDs total. So the probability of him picking a Tejano CD first would be . If he then picks a Rap CD without replacement, then the total number of possible CDs drops down to 9. Thus, the probability of him drawing a Rap CD after he draws a Tejano CD is
Does this make a little more sense now? If you're still lost, please post back.
Note that I moved your thread from the Geometry forum to the Probability and Stats forum.