It's stipulated that all points are iid.How exactly? I don't think Justin7 intended this to be, but this thread is turning out to be a great example between the differences of probability and statistics.
Lets say we wanted to look at the the % of times a 1H under hits when the full game under hits (which is basically this problem). We would need to make some "statistical inference" based on data collected to determine what is the relationship between the 1H total and the full game total. We could do this by looking at the 1H scores based on the full game total and model the relationship between them. Then we can use that data to determine the relationship between them.
In this example there's no data or implied relationship between them so we can't just assume one, therefore the way it is stated it is not calculable. You can't even go the route to assume every condition because the chances of all the conditions being equally likely is essentially 0.
If he gave some fixed probabilities or data about the relationship between 1st set and the total game then sure you can calculate it, but without that or data to determine a relationship between them you can't calculate anything unless you assume independence.