Show that if l ≥ 2, then every binary tree with l leaves contains a subtree having between l/3 and 2l/3 leaves, inclusive.

Answer and Explanation:

Proof by the using contradiction:

Let us assume that it isn't the situation and the statement is incorrect. Accordingly, the quantity of leaves in a subtree is either not as much as or more noteworthy than . Presently, on the off chance that we consider the subtree with number of leaves greater than leaves, we can say that there exists a subtree of the subtree referenced before that has more than leaves. Be that as it may, once more, thus the first explanations holds.

its either   1 , 21, 6,10, 21 ,36 depending on the answer choices you have.