What is the Inorder predecessor of 15 in the Binary Search Tree shown below

In a Binary Search Tree (BST), the inorder predecessor of a node is the largest value smaller than that node.

To find the inorder predecessor of 15, we look at its left subtree rooted at 6. The predecessor is the rightmost node in this subtree.

Starting from 6, we move right to 7, and then right again to 13. Since 13 has no right child, it is the maximum value in the left subtree.

Therefore, the inorder predecessor of 15 is 13.