Four out of five pair follow a certain rule and thus form a group, then which of the following pair doesn’t belong to that group? 

We have: The one who likes 2 sits 5m from left end, since only such combinations are (2, 3), (1, 1, 3) & (1, 2, 2). Two person sits between the one who likes 2 and T, who likes 8 and sits facing north. T neither sits at end of the row nor sits adjacent to N, that means we have four possible cases, in case (1) the one who likes 2 sits (2 + 3)r from left end, in case (2) the one who likes 2 sits (3 + 2)r from left end, in case (3) the one who likes 2 sits (1 + 3 + 1)r sits from left end, in case (4) the one who likes 2 sits (2 + 1 + 2)r from left end. N sits 4m left of the one who likes 8 and is 1m right of the one who likes 5, since only possible such combination is (1, 4). The one who likes 5 sits three places away from R, who doesn’t like odd number. R sits immediate right of the one who likes 6, thus in case (1a) R sits at right end and the one who likes 5 sits fourth from right end, in case (1b) R sits second from left end and the one who likes 5 sits fourth from right end, in case (2a) R sits at right end and the one who likes 5 sits fourth from right end, in case (2b) R sits second from left end and the one who likes 5 sits fourth from the right end, in case (3) & case (4) R sits third from left end and the one who likes 5 sits third from right end. Based on above given information we have: case-2b case-4 Again, we have: P sits third to right of the one who likes 3, since none of the adjacent person likes consecutive numbers. P neither sits adjacent to R nor likes even number, that means in case (1a), case (1b), case (2a) & case (2b) the one who likes 3 sits at right end facing south and case (3) & case (4) are not valid. The one who likes 4 sits 2m away from O. O sits 7m left of the one who likes 7, thus in case (1a) & case (1b) O sits at left end and N likes 7, in case (2b) O sits at right end and N sits facing south. Based on above given information we have: Case-1a Case (3) & case (4) are not valid as P sits third to right of the one who likes 3 and case (2a) is not valid as O sits 7m left of the one who likes 7. Again, we have: Q sits immediate right of the one who likes 1.  M sits 8m left of S, who neither likes prime number nor sits adjacent to the one who likes 4, that means in case (1a) & case (1b) M sits third from left end and S sits facing north, case (2b) is not valid.  P sits 6m right of Q, that means distance between S and Q is 1m and case (1a) is not valid. Q and R sits facing in same direction but opposite to the direction of M, that means R sits facing south and M sits facing North. Based on above given information we have final arrangement as follow: Case (2b) is not valid as M sits 8m left of S and case (1a) is not valid as P sits 7m right of Q. Case-1b