Answer:80 notebooks
Step-by-step explanation:
If n is the number of notebooks and t is the number of t shirts the 2 equations that can be made are this:
[tex]6n+12t=600\\n+t=90[/tex]
You can solve this by,
[tex]t=n+90\\6n+12(90-n)=600\\6n-12n+1080=600\\-6n=-480\\n=80\\\[/tex]So 80 notebooks.
