Answer:
Wall space between two junction boxes is
Step-by-step explanation:
We are given the following information:
Length of wall = 12 foot = 144 inches
Length of Junction box = 
There are two junction boxes to be arranged.
Total length of junction boxes = 
Space left:

Now, this left space have to be distributed in three equal part so that the arrangement could be of the form: space, junction box, space, junction box, space.
Space = 
Hence, wall space between two junction boxes is 