150- The degrees of non-1 vertices of a tree are $2,3,3,4,3,4,5$. How many vertices of degree 1 does this tree have? (1) $7$ (2) $9$ (3) $11$ (4) $13$
\textbf{150-} The degrees of non-1 vertices of a tree are $2,3,3,4,3,4,5$. How many vertices of degree 1 does this tree have?
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(1) $7$ \hfill (2) $9$ \hfill (3) $11$ \hfill (4) $13$
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