so, she can type 12 pages in 1 hour, how many would she type in 9 hours then? let's check,
[tex]\bf \begin{array}{ccll}
pages&hours\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
12&1\\
p&9
\end{array}\implies \cfrac{12}{p}=\cfrac{1}{9}\implies \cfrac{12\cdot 9}{1}=p[/tex]
so in 9 hours, she has that typed that many pages, how many pages remain from the 152? well 152 - p.
