Answer:
The answer is a. 320 books
Step-by-step explanation:
Hi
first of all, we can see "discount shelf for 70% off the regular price." is irrelevant info and a distraction, so we can use the info "If 2/3 of the books sold" then
[tex]BSold=\frac{2}{3} *960=640[/tex]
Now we can find the number of books remaining on the discount shelf [tex]BRemaining=960-640=320[/tex]