6 persons A, B, C, D, E and F are sitting in a row facing north (not necessarily in the same order). A is the immediate neighbour of D and F. F is the immediate neighbour of E and A. B is in the second position from the right end. If D is not at any of the ends, then how many persons are sitting towards the left of D?

A is the immediate neighbour of D and F. F is the immediate neighbour of E and A.

As per the above-given condition, there are two possible cases which are given below in Case(i) and Case(ii).

Case(i) D A F E

Case(ii) E F A D
B is in the second position from the right end.

After that only 'C' is remaining which can be placed on the blank space.

Case(i) (end) D A F E B C (end)

Case(ii) (end) E F A D B C (end)

If D is not at any of the ends.

Then Case(i) can be eliminated.

(end) E F A D B C (end)

According to the above arrangement, three people are sitting towards the left of D.