Ans : 17
Sum of Degrees of Vertices Theorem
If G = (V, E) be a non-directed graph with vertices V = {V1, V2,…Vn} then
n∑i=1 deg(Vi) = 2|E|
If the answer is 16 i.e. 16 Vertices of which degree of each vertex is 3 then Sum of degree of all the vertices is 48 but according to Sum of degree of Vertices therom it should be 2*25= 50. Hence, the answer should be 17.