8 @ 0.9
There are only 7 days in a week.
What 7 days? There are 8 ad slots available.
There are 10 total ad slots which are randomly rotated. So one ad slot has a one in ten chance of appearing. Eight of the slots are for sale here.
Oh. I thought that there there was 1 ad per day. I did not realize that it rotated. Sorry!