ANSWERS: 1
  • I would solve this by drawing it. But failing that: Take the vertex of degree 4, four loose edges attached. pick an edge and attach a vertex of degree 3 now you have five loose edges (one went in, two out). pick an edge and attach another vertex of degree 3 now you have six loose edges. The edges of degree 2 make no difference to the loose edges. All six loose edges must have a vertex of degree 1. So there are 6 vertices of degree 1. 3 + 2 + 1 + 6 = 12 vertices in all.

Copyright 2023, Wired Ivy, LLC

Answerbag | Terms of Service | Privacy Policy