I think it would be 16.95 Hope this help you in someway.
Answer = 16/5 or x(1)=0
X •(5x-16)=0
X=0 and 5x-16=0
5x-16=0 then solves into 16/5 (fraction form or 3.2 decimal)
There are 15 biography books and there are 48 books in total so the ratio is 15:48
64
64 is divisable by 2, 8, and 16, and also between 55 and 101