The seating arrangement of given 14 persons at the round table as shown below.
Number of ways of selecting 2 persons out of 14 persons = 14C2 = (14 x 13)/(1 x 2)
In the above arrangement two persons sitting adjacent to each other can be selected in 14 ways. (they are a1a2, a2a3, ........ a13a14, a14a1)
∴ The required no. of ways = 91 – 14 = 77
