Thread: Vertices help

Hey guys need help with this question. "A graph has 33 edges, and every vertex has degree 7 or degree 8. How many vertices does the graph have?".

Any help would be much appreciated.

From the handshaking lemma




Since there are edges, that means .


That means that , where is the number of vertices with degree and is the number of vertices with degree .


By inspection, and .

So there are vertices.

Originally Posted by Prove It

From the handshaking lemma




Since there are edges, that means .


That means that , where is the number of vertices with degree and is the number of vertices with degree .


By inspection, and .

So there are vertices.

Thank you for your reply! Nice and clear.