Answer:
[tex]\frac{1}{4}[/tex] of the books in the book store are mystery fiction books.
Step-by-step explanation:
Let x represent all the books in the books store.
Then, the fraction of books that are fiction books is [tex]\frac{3}{4}x[/tex]
We have that; [tex]\frac{1}{3}[/tex] of the fiction books are mystery books.
The fraction of the books at the bookstore that are mystery fiction books is [tex]\frac{1}{3}\times \frac{3}{4}x=\frac{1}{4}x[/tex].
Therefore [tex]\frac{1}{4}[/tex] of the books in the bookstore are mystery fiction books.
