A recipe for cookies calls for 7 1/2 cups of flour. If the recipe is for 2 dozen​ cookies, how much flour is needed for 13 dozen​ cookies?

2 answers

7.5/ 24 = x/156

Cross multiply and solve for x.
You want 13/2 as many cookies, so use 13/2 as much flour:

(13/2) * (7 1/2) = 48 3/4 cups