# # of vertices and # of connected components proof problem?

Let G be a graph with 15 vertices and 4 connected components. Prove that G has at least one component with at least 4 vertices. What is the largest number of vertices that a component of G can have?

Read over connected components for a long time and still have no idea how to prove this.

• If each of the four components has three vertices the total number of vertices is $12$, so you can't have $15$. – Ross Millikan Jan 25 '18 at 15:33