Seven persons D, E, F, G, H, I and J sit in a linear row and face towards north direction. Who sits second to the right of J? Statement I: F sits second from an extreme end. Only three persons sit between F and E. H sits adjacent to E. G sit third to the left of H. J doesn't sit adjacent to G. Statement II: E sits fourth to the right of F. Neither E nor F sits at an extreme end. D sits second to the left of
I. G sits to the left of H and to the right of J.

From statement I, F sits second from an extreme end. Only three persons sit between F and E. H sits adjacent to E. G sit third to the left of H. J doesn't sit adjacent to G. We get: J          F          D/I       G         I/D       E         H From statement I alone, we get either D or I sits second to the right of J. From statement II, E sits fourth to the right of F. Neither E nor F sits at an extreme end. D sits second to the left of I. G sits to the left of H and to the right of J. We get: Case 1: J          F          D         G         I           E         H Case 2: J          F          G         H         D         E         I Case 3: D         F          I           J          G         E         H   From statement II alone, we get one of the persons among D, G or E sits second to the right of J. Combining statement I and II together, we get: J          F          D         G         I           E         H So, from statement I and II together, we get D sits second to the right of J. Therefore, data given in both statement I and II together are necessary to answer the question.