Answer:
12
Explanation:
Number of novels in the book collection of Riley = 40
Ratio of fictional novels in the book collection =

Number of fictional novels = Ratio of fictional novels in the book collection × Number of novels in the book collection of Riley =

Ratio of fictional novels written by Michael Crichton =

Number of fictional novels written by Michael Crichton = Ratio of fictional novels written by Michael Crichton × Number of novels in the book collection of Riley =

Therefore, number of novels that Riley has in the book collection of Michael Crichton = 12