5:2 ratio means there are 7 books in total.
nonfiction is 5, and fiction is 2
It's like saying you have 5 boxes on top and 2 on the bottom
if we take 1421 and divide by 7, we get 203 books per box.
so that means we would take the number of books per box and multiply it by the number of boxes.
this means for nonfiction books, we take 5 and multiply it by 203 and get 1015.
for fiction, we have 2 boxes and multiply it by 203, and we get 406.
if we add 406 and 1015, we get 1421, and that's how we can calculate our nonfiction and fiction books.
hope this helps. look up ratio tape diagrams in case that can clear things up.