I need to know what 2/5 of 56 is in a full number

Question

In the library there are 2/5 as many fiction books as there are non-fiction books, there are 56 books in the school library. How many books are fiction books?

Answer 1

Let F = the number of fiction books Let N = the number of non-fiction books

F=(2/5)N

F+N=56 substitute (2/5)N for F in the sum equation

(2/5)N+N=56

(2/5)N + (5/5)N = 56

(7/5)N = 56

N = (5/7)56 = 5(8) = 40 non fiction books

F = 56-40 = 16 fiction books

16 is (2/5)(40)