What is the total distance between D and F when counting

Solution

The circumference of a circle is 468m. They are sitting at distances to each other which are multiple of 6 .It means the distance between first person and second person is 6m then the distance between second person and third person is 12, and the distance between third person and fourth person is 18m and so on. Distances are increasing in clock wise direction. Given number of person is 12.So the possible combination is (6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66 and 72. The distance between N and C is multiple of 5 which is less than 70m but more than 40m. Two persons are sitting between N and M. B sits 78m away from M. D sits opposite to B. Three persons are sitting between D and Q. Neither Q nor M is an immediate neighbor of E. O sits third to the left of E. G and O are immediate neighbors. A and P are not immediate neighbors. The distance between F and P are less than 100m.F is not sitting opposite to G. Thus case 1b is the final arrangement.