We have been given work of Riley. By looking at his work carefully, we have to identify the error. So let's start from beginning.

First line is just the question so there will be no error.
After that we try to factor denominators
STEP1: 
Factors are correct so no error in step1.
In step2, we have to find the common denominator which will be (x-2)(x-3)(x+3)
so that means she needs to multiply and divide 2nd term by (x-2)(x-3) while she multiplied by only (x-2). Which means she used wrong common denominator.
<u>Hence final answer will be "B. She used the wrong common denominator."</u>
20/12 = 1.6 recurring (that is, 1.6666...)
B) 14.
If you start with subtracting the 8 pages from 50, you get 42 remaining pages. Then it says 2/3 of the REMAINING pages so you divide 42 into thirds. 42/3=14. You want 2/3 of that, so you multiply the 14 by two to get 28 (it's like there are three piles of 14 pages and you want only 2 out of the three piles). So now you've used 28 pages + the original 8. You've used a TOTAL of 36 pages. Subtract 36 from 50 and you get 14 left.
2=28 divide both get 14 . So each cd is 14$. So now 28+28=56 (4 cd's) plus 14 (1 more cd) =5 so 5 is 70.