is anyone can give explanation pls

[sanjib]

Are the numbersk/4,z/3 and r/2 in increasing order?
(1) 3 < z < 4
(2) r < z < k
Need help pls.

[GMATQuantCoach]

(1) Choose k = 0 r = 0 z = 3.5. Then they are not in increasing order.
Choose k = 0, r = 100 z = 3.5. Then they are in increasing order.
Insufficient.

(2) Choose k = 100, z = 99, r = 98. Then they are in increasing order.
Choose k = -98, z = -99, r = -100. Then they are in decreasing order.
Insufficient.

When combined,

Let z = 3.5, r = 3.499999, k = 3.500001. Just by estimating, they are in increasing order.

Let z = 3.5, r = 0, k = 100. Then they are in decreasing order.

Insufficient.

Answer is E.