Hello! For question #31, the question says “meter stick” so the total length of the rod is 1m. With the left side of the rod (relative to the pivot point) being 20 cm, the right side must be 80 cm.
In question #42, the pulley acts as a modified lever due to the pivot points being off-center. This causes a difference in tension.
We'll loop back to question #35 shortly.