Answer to Question #300990 in Discrete Mathematics for Ace

Question

How many edges are there in a graph with 15 vertices each with degree 8?

Answer 1

Let m be the the number of edges

Because the sum of the degrees of the vertices is

$15 \times8 = 120$ , the handshaking theorem tells us that $2m = 120\implies m=60$ .

So the number of edges m = 60.