Emily has 85 books on her book shelf of those books 20% are mysteries 18 are adventur story's and the rest are fantasies. What is the simplified ratio of fantasies to total books on her bookshelf?

First find the number of mysteries by multiplying 85 books by 20%:

80 x 0.20 = 17

Now add mysteries and adventure books together and subtract from 85 to find the number of fantasy books:

17 + 18 = 35

85 - 35 = 50

So 50 out of 85 books are fantasy.

This is written as 50/85 which simplifies to 10/17.