Answer:
Jacob will need eleven shelves in order to stack all the books
Step-by-step explanation:
(9)=1 shelf
(18)= 2 shelves
(27)= 3 shelves
(36)= 4 shelves
(45)= 5 shelves
(54)= 6 shelves
(63)= 7 shelves
(72)= 8 shelves
(81)= 9 shelves
(90)= 10 shelves This isn't enough because he has 6 more..therefore
In order to fit 96 books on the library shelves Jacob needs to stack 11 shelves.