(Question 2) Let G be a connected graph with a planar embedding. Suppose every vertex in G has degree 4, and that every face in the embedding has degree in {3, 4}. (a) How many faces of degree 3 are there? (Note: an answer based on example of a graph satisfying these properties is not sufficient.) (b) If there are 10 faces of degree 4 in the embedding, how many vertices are there in G? Hint: this problem is asking you to prove some structural property of a planar graph. We learned a limited set of tools to tackle this sort of problem. If you get stuck, reread the problem. What piece of information have you not used yet? If f is the number of faces in the embedding, it might be helpful to define numbers fa and fa where f = f3 + f4