Explanation #1: It seems that Rava's opinion is based on his understanding in Eiruvin (68a) regarding a baby whose hot water for his Bris was spilled. Rava said, "Let us ask the baby's mother. If she needs hot water, we can heat up more water for the baby once we are heating it for the mother."

Explanation #1 (cont.): It seems that this happened on the eighth day before the Bris, as they needed hot water to go ahead with the Bris as if he does not have hot water after the Bris it is dangerous, and at that point they would desecrate Shabbos for him. Accordingly, this incident must have occurred after the seventh day, as when the womb is closed we require her to need water to desecrate Shabbos for her.

Implied Question #1: However, according to the version that Rava holds thirty days, one could ask why Rava in Eiruvin (ibid.) required that she should say she needs hot water. (Why does she need to ask?)

Implied Question #2: Additionally, Rashi in Eiruvin (ibid.) explains Rava's question to be that we should ask a Nochri to heat up the water for the mother. This is also the explanation of Rabeinu Chananel. (Why should this be required according to the version of thirty days?)

Explanation #2: This is why the explanation appears to be that Abaye and Rava are each saying separate statements and they are not arguing. They both agree with Neharda (that there are three separate times: 3, 7, 30 etc.).

Explanation: Before the decree of Ezra, even though they would judge every day they needed to judge, they would not permanently sit (and be available) on a certain day.

Implied Question: Wednesday also has two appearances of Madim, including one at the end of the day. (Why is one allowed to blood let on Wednesday?)

Answer: The sages were not worried about this, as it is not common to blood let so close to nightfall.

Explanation: This means that there is not four days left to the end of the month, as Rashi explains. One cannot say that it means Wednesday, as "four meaning twenty four" means there are no Wednesdays afterwards in that month.

Question: According to Rashi's explanation, why is this in our Gemara?

Explanation: Rabeinu Chananel has the text "One hundred Karni for a Zuz." He explains that the previous statement, "one hundred heads for a Zuz" means that it was a set custom for the barbers to cut hair for a Zuz. Similarly, the phrase, "one hundred blood letters" means it was the custom to do bloodletting for a Zuz. "Karni" is from the term "Karna d'Umna" (154b, meaning blood letters).

Explanation (cont.): However, one hundred mustaches, meaning to fix and trim one hundred mustaches costs nothing. This is because when someone would pay for a haircut and blood letting (the same person usually did both), he would also fix and trim his mustache. When he would trim and fix a mustache, he did not receive any extra wages. This therefore is a parable that whoever toiled and did not receive money would say he had "a mustache day."

Explanation: They became weak, and were weak to the point that they could not learn Torah.

Proof: This is as the Pasuk states in Shmuel, "And David chased, him and four hundred men, and two hundred men stopped as they were too weak to cross Nechal Besor."

Explanation: This is not a derivation from the Pasuk. Rather, it must be that if it is in the Parshah of the curses that it is painful if one does not attend to it. The sages therefore allowed attending to these things, as none of these treatments involves a Torah prohibition.