(i). A, B, C, D, E and F are six students in a class.
(ii). B and C are shorter than F but heavier than A.
(iii). D is heavier than B and taller than C.
(iv). E is shorter than D but taller than F.
(v). F is heavier than D.
(vi). A is shorter than E but taller than F. Which of the following groups of friends is shorter than A ?

Answer: D. F, B, C only

In terms of height, we have :
B < F, C < F, C < D, E < D, F < E, A < E, F < A.
So, C < F <  E < D, B < F, F < A < E
Thus, the sequence becomes :
B < C < F < A < E < D or C < B < F < A < E < D.
In terms of weight, we have :
A < B, A < C, B < D, D < F.
So, A < B < D < F, A < C.
Thus, the sequence becomes :
A < C < B < D < F or A < B < C < D < F or A < B < D < C < F.


Clearly, F, B and C are shorter than A.