there is 20x more nonfiction than fiction so you do
20+1=21
so then to find out what [tex]\frac{1}{21} [/tex] of 1155 is we do
1155÷21=55
so then we times 55 by 20 because there are 20x more nonfiction than fiction
55x20=1100
soo now we know there is
1100 nonfiction books and
55 fiction books
to check whether we are right we can do
1100=55=1155
we are right because there is 1155 books in the library
hope i helped