There are 5 shelves in the bookcase.
2/5 of one shelve is occupied.
That would be:
2/5*1/5=2/25 of all shelves
7/2 is more than 1, so it refers to the bookcase instead of one shelve. The same with 11/10.
So the total is:
2/5+7/2+11/10 = 5
So all shelves are completely full.
So there is no room for any other book.