10 questions · Form 4 Mathematics Bab 5: Network Theory
In a transportation network graph, what do weighted edges usually represent?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. In a transportation network graph, what do weighted edges usually represent?
Answer: C
Weights in transportation networks denote physical quantities between nodes, such as travel distance, duration, or cost.
2. Which statement is true regarding the sum of in-degrees and out-degrees in a directed graph?
Answer: C
Every directed edge originates from one vertex (out-degree) and ends at another (in-degree). Thus, sum d_in(v) = sum d_out(v) = E.
3. What is a weighted graph?
Answer: B
A weighted graph is a graph in which each edge is assigned a numerical weight representing quantities like cost, time, or distance.
4. If a tree has 9 vertices, how many edges must it have?
Answer: A
In any tree, the relation between vertices (V) and edges (E) is given by E = V - 1. So E = 9 - 1 = 8.
5. How many degree count contributions does a single loop at a vertex add to that vertex?
Answer: C
A loop connects a vertex to itself and both ends touch the vertex, adding 2 to the degree count of that vertex.
6. What is the total sum of degrees for a graph with vertices V = {A, B, C, D} and degree of vertices d(A)=3, d(B)=2, d(C)=4, d(D)=3?
Answer: C
Sum of degrees = d(A) + d(B) + d(C) + d(D) = 3 + 2 + 4 + 3 = 12.
7. Given set V = {1, 2, 3, 4} and set E = {(1, 2), (1, 3), (2, 3), (3, 4)}. What is the degree of vertex 3?
Answer: C
Vertex 3 appears in three edge pairs: (1, 3), (2, 3), and (3, 4). Therefore, its degree is 3.
8. If a graph has 4 vertices with degrees 1, 2, 3, and 2 respectively, how many edges does it contain?
Answer: A
Sum of degrees = 1 + 2 + 3 + 2 = 8. Using sum d(v) = 2E: 8 = 2E, so E = 4.
9. In a directed graph, if a vertex has an in-degree of 3 and an out-degree of 2, what is its total degree?
Answer: B
Total degree of a vertex in a directed graph is the sum of its in-degree and out-degree: 3 + 2 = 5.
10. Given that the sum of degrees of a graph is 18, calculate the number of edges in the graph.
Answer: B
Using sum d(v) = 2E: 18 = 2E, which gives E = 182 = 9 edges.