Answer:
Coroline bakes 12 dozens of cookies in all.
Explanation:
Given: Caroline baked 3 dozen oatmeal raisin cookies for the bake sale at school. This is one fourth the number of dozens of cookies she baked in all.
We have to find the number of dozen cookies she bake in all.
Note: 1 dozen = 12
So, Caroline baked 3 dozen oatmeal raisin cookies for the bake sale at school this means she bakes 12 × 3 = 36 oatmeal raisin cookies.
Also, given Number of oatmeal raisin cookies is one fourth the number of dozens of cookies she baked in all.
This means ,

Let the number of cookies she bakes be x .
that is,

Solve for x, We get
x = 144
Thus, number of cookies did she bake in all is 144.
Since we have to find in dozen divide 144 by 12 , we get, x = 12
Thus, Coroline bakes 12 dozens of cookies in all.