Carlos is arranging books on shelves. He has 24 novels and 16 autobiographies. Each shelf will have the same number of novels and autobiographies. If Carlos must place all of the books on shelves, what are the possible of shelves Carlos will use?
If Carlos must place all the books on shelves, he may possibly use 10 shelves if he is to place 4 books per shelf, or 5 shelves if he is to place 8 books on each.