1.
HG Schild asks:
Why is the Bnei Berak Baraisa repeated?
Reasons given? Common?
chaim
hg
2.
The Kollel replies:
Shalom,
It seems that on the bottom of 154a that Baraisa is brought as a challenge to R' Lakish's (and Rav Chisda's) view that Kiyum Shtar suffices as a Rayah. Whereas on the bottom of 155a the Baraisa is brought as a challenge to Rav Huna Bar Chanina's view that the sale needs to be from 20 years of age.
I hope this helps!
Warmest regards,
Yishai Rasowsky