Greetings!
11/4=2.75
To make 11 dozen cookies, you would need to make 2.75 times the recipe.
Therefore, you will need 2.75 times the brown sugar:
[tex]3/4*2.75[/tex]
[tex]=3/4*2 \frac{3}{4} [/tex]
Convert the mixed fraction into an improper fraction.
[tex]=3/4*11/4 [/tex]
[tex]=33/16[/tex]
Convert back into a mixed fraction.
[tex]=2\frac{1}{16} [/tex]
You would need 2 1/6 cups of brown sugar to make 11 dozen cookies.
Hope this helps.
-Benjamin
