Ans: ²⁄₇
There is 7 people excluding you and there is a seat to the right of you and the left of you. There is 1/7 probability for me to sit in either of these seats. So 1/7+1/7 = 2/7.
Note : This is true only if the number of chairs is exactly equal to the number of people. We can view the answer in a different perspective, If the number of chairs is 8, then one is taken by you. I can only choose 2 favourable chairs (left and right of you) out of 7 remaining.
