In Henry's collection of music CDs, he has 3 more country CDs than rock CDs but twice as many rock CDs as classical CDs. If he has 23 country CDs, how many classical CDs make up his collection?
Henry has 23-3=<<23-3=20>>20 rock CDs.
Henry has 20/2=<<20/2=10>>10 classical CDs.
#### 10