74) The maximum number of nodes on level i of a binary tree is

75) The smallest number of key that will force a B-tree of order 3 to have a height 3 is

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