Let's make a Venn diagram to answer this question. 
We can put all the information we know into a Venn diagram. Since Andrew has 17 total, we can say that 17-9=8 CD's are Andrew's and not John's. The question is asking how many albums are in either Andrew's or John's collection, but not both? So, we can add up the numbers in only Andrew's and only John's. Then we get 8+6 which is equal to 14 CD's in total.
