Out of a sample of 80 books, 6 were historical books. So the percentage of books in the sample will be:
[tex] \frac{6}{80}*100= 7.5 [/tex]%
We can use this sample to represent the entire collection of books in the library. So the best estimate of total number of historical books in the library is 7.5% of 21360 , which comes out to be:
7.5 % of 21360 = [tex]0.075(21360)=1602[/tex]
Therefore, roughly 1602 books out of 21360 book of library are historical books.
