The base rent is $3,100 for 12 people + $200 for cleaning. The cost per additional person is $175 for the week. We had 20 people wanting to come, making the rent $4,700.
I told the owner after a few weeks of collecting that we may not get the numbers we stated initially. She said not to worry as we will only be charged for the number of people we have in the end, not how much we promised.
No matter what happens, we must pay $3,300. I was simply warning that if no one else comes, the new rent for the twelve of us will be $275, hence the $40.