Is there a tree with seven vertices:
a) With five vertices having degree 1 and two vertices having degree 2? b) With vertices having degrees 2,2,2,3,1,1,1?
So I believe the degree is the number of children vertices there are from the vertex? For a) I believe the answer is yes because I was able to draw a tree as such but for b) I believe the answer is no because I could not conceptualize a tree like this.
I may be taking the wrong definition of degree though or might be thinking about "rooted" trees only. Thank you for any help clarifying this concept and if there is a formula/ theorem for this.
HINT
Since every edge will connect exactly two vertices, every edge you add to a graph will increase the sum total of all degrees of all vertices in the graph by $2$. So ... the sum total should always be what kind of number?
So, count a little harder for whatever you drew for a) ...
Also, try a little harder for b) ...