Question

8 different persons are sitting around a table. Numbers of ways in which we can select 3 of them so that no two are consecutive is 

(A)  12 

(B)  16 

(C)  15 

(D)  22

Answer 1

Correct option  (B) 16

For n persons sitting around a table, number of ways of selecting 3, of which no two are consecutive is equal to no side of triangle is common with n sided regular polygon is given by

1/6n(n - 4)(n - 5).

Put n = 8.