In a binary search tree ,the key with value 5 was searched after traversing nodes with values 1,3,4,6,7,8,9 not necessarily in that order.
Let P is the probability that 3rd element on the search path beginning from the root is either 3 or 8.and N are the number of different order possible in which given nodes can be traversed before finding node with value 5 .Find (N/10)+P