76) A binary tree in which every non-leaf node has non-empty left and right sub-trees is called a strictly binary tree. Such a tree with 10 leaves

77) Number of possible binary trees with 3 nodes is

78) A-2-3 tree is a tree such that
1. All internal nodes have either 2 or 3 children.
2. All paths from root to the leaves have the same length.
The number of internal nodes of a 2-3 tree having 9 leaves could be

79) A binary tree is generated by inserting in order the following integers:
50, 15, 62, 5, 20,58, 91, 3,8,37, 60, 24 . The number of nodes in the left of the root respectively is

80) Consider the following nested representation of binary trees indicates y and z are the left right subtrees, respectively, of node x. Note that y and z may be NULL or further nested. Which of the following represents a valid binary tree ?