Two persons A, B and 8 others are arranged in a row at random. In the arrangement if A is not at the starting place or the ending place, then the probability that A, B are adjacent to each other is ….. 

Consider 10 placed numbered from 1 to 10.  A is not in places 1, 10 as per given condition. Then to arrange B there are 9 places of which 2 adjacent places to A are favorable to the event that A, B are adjacent 
$\to$  required probability = 2/9