The number of books that Ballio was able to read can be determined by multiplying the number of boxes he checked out and the number of books per box. This is as shown below,
N = (3 boxes)(9 books/box)
N = 27 books
Since, it is stated that he beat his goal by 4 books, his goal is equal to the calculated number minus 4.
Goal = 27 books - 4 books
Goal = 23 books
ANSWER: 23 books