I will assume here that the dimensions of the office are 12x32x25 feet - I think that this is what your question is mentioning.
This means that the whole volume of the room is:
12x32x25=384*25=9600
So, if you want to measure how much they will pay in the whole year, it will be:
9600*0.11=1056 dollars.
But this is per year! how much would it be per month? we divide by 12:
1056/12=88
So they would pay 88 dollars a month
