Trees & BST

The height of a binary tree is the number of edges in the longest path from the root to a leaf in the tree. The maximum possible height of a full binary tree with 23 nodes is _________. (*answer in integer*)

Let $P$ be the set of all integers from 1 to 15. Consider any order of insertion of the elements of $P$ into a binary search tree that creates a complete binary tree. Which one of the following elements can NEVER be the third element that is inserted?

The following sequence corresponds to the preorder traversal of a binary search tree $T$: $$50, 25, 13, 40, 30, 47, 75, 60, 70, 80, 77$$ The position of the element 60 in the postorder traversal of $T$ is ______. (*answer in integer*) *Note:* The position begins with 1.