Answer:
1 book per shelf
Step-by-step explanation:
So, there's 20 books, and Jeremy has 4 shelves
If Jeremy arranges the books equally. so each shelf has the same out of books, do 20 / 4 to get the amount of books per shelf
20 / 4 = 5 books per shelf
Now, if Brandon takes away 4 books from each shelf, do 5 - 4 to find the remaining amount of books per shelf
5 - 4 = 1
1 book per shelf left