In a binary tree, the number of internal nodes of degree 1 is 5, and the number of internal nodes of degree 2 is 10. The number of leaf nodes in the binary tree is
(A) 10
(B) 11
(C) 12
(D) 15
Answer: (B)
Explanation: In a binary tree, the number of leaf nodes is always 1 more than number of internal nodes with 2 children, refer https://www.geeksforgeeks.org/handshaking-lemma-and-interesting-tree-properties/amp/
So,
Number of Leaf Nodes = Number of Internal nodes with 2 children + 1
Number of Leaf Nodes = 10 + 1
Number of Leaf Nodes = 11
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