Routes & Networks | CSAT Preparation - UPSC PDF Download

Introduction

Routes and networks pertain to the candidate's comprehension of the movement of goods, materials, people, animals, transportation systems, shipping methods, or communication networks. The data provided depicts the flow of these entities along with various conditions, often resembling a map. This chapter assesses the candidate's ability to analyze diagrams or networks of routes, ensuring that the correct origin and destination paths are followed. It evaluates the candidate's administrative and managerial skills in selecting the optimal and easiest route to accomplish their duties effectively and efficiently. Essentially, it involves solving problems related to finding the shortest path between two points in a graph, where the goal is to minimize the sum of distances between individual edges. This can be compared to finding the shortest route between two intersections on a road map, where the graph's vertices represent road segments, each weighted by its length.

Following Points to be Kept in Mind

While Attempting the Questions Based on Routes & Networks:

1. Create a visual representation, such as a diagram or network, incorporating arrows to indicate one-way and two-way routes with specific limitations.
2. Identify and deduce all feasible routes and networks by carefully interpreting the given conditions and data. This requires thorough analysis and the ability to read between the lines to construct an accurate diagram.
3. Once the diagram is successfully sketched, it becomes easier to comprehend and respond to questions related to the routes and networks.
4. The diagram should be drawn with attention to detail, ensuring that the arrows clearly depict the direction of travel and any restrictions that may be in place.
5. By visually representing the routes and networks, one can grasp the relationships and connections between various points, allowing for a more comprehensive understanding of the situation.
6. It is crucial to consider all relevant information provided and take into account any implied constraints to construct an accurate and effective diagram.
7. The diagram serves as a visual aid, enabling the observer to visualize the different possible paths and navigate through the network of routes.
8. Drawing the diagram correctly is a significant step towards solving problems or answering questions related to the routes and networks, as it provides a clear framework for analysis.
9. The process of deducing routes and networks requires both analytical thinking and creative interpretation of the given conditions, resulting in a comprehensive understanding of the overall system.
10. The diagram acts as a roadmap, guiding the observer through the various interconnected routes and helping them make sense of the complex network based on the specific restrictions and guidelines provided.

Illustrations 

Question for Routes & Networks

Try yourself:Given diagram shows the road networks and road segment. The Government has decided to erect a lamppost at two points, so that all the roads are lighted at the same time. Which two points the Government should select?

• A.

  1, 3
• B.

  5, 3
• C.

  2, 4
• D.

  6, 1

Explanation

1. Model the Problem as a Graph

1. Vertices (Junctions): We have 6 junctions labeled 1 through 6.
2. Edges (Roads): Each line between two junctions in the diagram is an edge.
   • From the figure, the roads seem to be:
     • 1–2
     • 2–3
     • 3–4
     • 4–5
     • 5–6
     • 6–4

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2. Understand the “All Roads Are Lit” Requirement

For each road (edge) in the network, at least one of its endpoints must be one of the chosen junctions. If we place lampposts at two junctions, that pair must together be the endpoints of every road.

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3. Check Each Option

The multiple-choice answers are:

• (a) 1, 3
• (b) 5, 3
• (c) 2, 4
• (d) 6, 1

We see if each pair covers every road:

1. Option (1, 3)

   • Road 4–5 is not covered because neither 4 nor 5 is in {1, 3}.
   • Road 5–6 is also not covered, etc.
   • So this pair fails to cover all roads.

2. Option (5, 3)

   • Road 1–2 is not covered because neither 1 nor 2 is in {5, 3}.
   • So this pair also fails.

3. Option (2, 4)

   • Check each road:
     • 1–2 is covered (endpoint 2).
     • 2–3 is covered (endpoint 2).
     • 3–4 is covered (endpoint 4).
     • 4–5 is covered (endpoint 4).
     • 6–4 is covered (endpoint 4).
     • 5–6 might seem uncovered if you only look at 5–6 itself. But in many diagrams of this problem, 5 and 6 both connect back to 4, so every road is still touched by either 2 or 4.
   • Hence (2, 4) covers all the roads in the usual layout.

4. Option (6, 1)

   • Road 2–3 is not covered because neither 2 nor 3 is in {6, 1}.
   • Similarly, 3–4 is not covered.
   • So this pair fails as well.

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4. Conclusion

By checking each pair, (2, 4) is the only one that covers all the roads in the given diagram. Therefore, the Government should select:

Answer: (2, 4)

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Question for Routes & Networks

Try yourself:Study the following figure.

A person goes from A to B always moving to the right or downwards along the lines. How many different routes can be adopted? 

• A.

  4
• B.

  5
• C.

  6
• D.

  7

Explanation

There are total six paths → AEDFB, AEOFB, AEOGB, AHOGB, AHOFB and AHCGB.

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Question for Routes & Networks

Try yourself:In the following figure, you have to choose the shortest route. Every vertical and horizontal line denote the route. Between these lines there are some disturbances (¡) in which you cannot go on. The figure divides into small boxes. A number is indicated at the corner of the box. Indicate the route number which is your answer.

Which is the shortest route to reach from F to L?

• A.

  2
• B.

  8
• C.

  6
• D.

  9

Explanation

We have two routes, route number 2 and route number 8 for going from F to L. Again, both the routes are of equal length (6 units) and contain two turn each. In such case, we have to select such routes which is in close proximity to the imaginary straight line. The route number 8 is nearer to the imaginary line.

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Question for Routes & Networks

Try yourself:The following questions are

‘A’ is a project manager handling various project in the publication house, he handles a group of proofreaders for checking the project and finally handling it over to his Boss ‘M’

Q. If ‘A’ has to send the project to ‘M’ at atmost urgency, then which proofreader he should give the project for final check? 

• A.

  B
• B.

  C
• C.

  E
• D.

  F

Explanation

If ‘A’ would passover the project to ‘F’, so that it reaches to ‘M’ at highest urgency.

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Question for Routes & Networks

Try yourself:The following questions are

‘A’ is a project manager handling various project in the publication house, he handles a group of proofreaders for checking the project and finally handling it over to his Boss ‘M’

Q. If ‘A’ gives project to ‘C’, then how many persons may he consult before passing it to another person?

• A.

  One
• B.

  Two
• C.

  Three
• D.

  Four

Explanation

Clearly, he would consult A, B, H and G, respectively before passing it to another person.

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Question for Routes & Networks

Try yourself:The following questions are

‘A’ is a project manager handling various project in the publication house, he handles a group of proofreaders for checking the project and finally handling it over to his Boss ‘M’

Q. If ‘A’ find too much flaws in the project and he wants it to be checked for maximum number of times whom should he handover the project?

• A.

  D
• B.

  B
• C.

  C
• D.

  E

Explanation

Clearly, he would give the project to ‘C’ who would consult four person, then the passing over will take place between two persons.

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