1 is insufficient because we don't have any info about k and r.
2 is insufficient if you consider two examples:
a. r = 1, z = 3.6 and k = 12 - in this case:
r/2 = 0.5
z/3 = 1.2
k/4 = 3
The correct order would be r/2 < z/3 < k/4, which means that the answer to the question in the stem will be NO.
b. r = 3.2, z = 3.3 and k = 3.6 - in this case:
r/2 = 1.6
z/3 = 1.1
k/4 = 0.9
The correct order will be k/4 < z/3 < r/2 - so the answer to the initial question will be YES.
Since we get two conflicting answer depending on the numbers we chose, then 2 is insufficient as well.
There's a reason I chose 3 < z < 4 in both cases outlined at point 2 above. This is because the two examples also prove that both statements taken together are not sufficient, since in both instances we have z between 3 and 4, with r < z < k.