Question 5 asks: "If one throws four Amos at sea, he is _______ .". The answer that is called correct is "Hiav". This is hard to reconcile with the statement in the Mishnah, which explictly says that he is Ptur in such a case. Wouldn't the see as a karmalis be at most asur derabanan?

Question 2 may also be problematic:

One who throws a mat into a pit ten Tefachim deep and exactly eight Tefachim wide dividing it into two, he is _________ . You state in the explanation for the answer that חילקה ב מחצלת פטור לאביי דפשיטא ליה דמחצלת מבטלא מחיצה כל שכן חוליא דמבטלא מחיצה לרבי יוחנן דמיבעיא ליה חוליא מחצלת פשיטא דלא מבטלא מחיצת.

If in fact it is pashut to R"Y that the mechitza does not mvatel, then it should follow that he is patur. So the correct answer would seem to me to be Machlokes A&B. In fact, that is the simple meaning of the gemora. That said, it seems to me that the Kal VeChomer for Abaye is clear, but the kal vehomer doesn't precisely hold for R"Y, so in svara the answer that you give does seem to me to make sense there. But, it seems wrong to take off points for answering like the gemara states explicitly.

Yisroel Yakovson, Beitar, Israel