Recall that the ratio of two quantities x and y is the fraction
[tex]\frac{x}{y},[/tex]or x:y, which indicates how many times y is the quantity x.
Now, if there are 4 new books, then there are 11-4=7 old books.
Therefore, the ratio of new books to the old books is:
[tex]\frac{4}{7}\text{.}[/tex]The ratio of old books to new books is:
[tex]\frac{7}{4}\text{.}[/tex]Answer:
New to old: 4/7.
Old to new: 7/4.