1d) the keyword nonzero escaped me for the first time, and made me think 	
    there was a bug in the question. Maybe it'd help if we capitalize it?

1e) are we allowed to draw in picture instead?

2c) and 2d) are rather difficult to understand what they are asking when 
    I first looked at it. Personally, I'd prefer wording such as 
    "What is the number of Ringwraiths in the best/worst case scenario"

8c) I am not sure if that would make it too obvious. But it would be easier 
    for them to pinpoint the error if we add a line 

	P(T|O) = P(T|there is at least one girl in the household)


10 a) and 10 b): The wording "I must watch" makes me feel that I am asked 
    to give a bound on the number to guarantee watching a great episode, 
    (even though I can definitely guess what it's asking). I think 
     changing it to "need to watch" may help.


Problem 13, the figure number is missing.