GATE CS 2021 Set 1 — Question 27
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.NAT+1 / -0MediumTrees & Spanning TreesGraph Theory (Math)Engineering MathematicsKruskal's MSTGreedy AlgorithmsAlgorithms
Algorithms → Graph Theory (Math) → Kruskal's MST
Last updated
Question
Consider the following undirected graph with edge weights as shown:
The number of minimum-weight spanning trees of the graph is _______.

Correct answer
3 to 3
Solution
To find the number of minimum-weight spanning trees (MSTs), we consider the edges with the minimum weight, which is 0.1.
Let the vertices be labeled as follows:
Top row:
Bottom row: From the graph, the edges with weight 0.1 are:
Let the vertices be labeled as follows:
Top row:
Bottom row: From the graph, the edges with weight 0.1 are:
1.
2.
3.
4.
5. (diagonal)
6. (diagonal)
There are 6 edges with weight 0.1. Let's check for cycles among these edges:- The edges form a cycle of length 3.
- No other cycles are formed by these 6 edges, and they connect all 6 vertices.
- Removing leaves a tree.
- Removing leaves a tree.
- Removing leaves a tree.
Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE CS question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Graph Theory (Math)
2026 Set 2 Q3A day can only be cloudy or sunny. The probability of a day being cloudy is , independent of…2026 Set 2 Q5‘When it is raining, peacocks dance.’ Based only on this sentence, which one of the following…2026 Set 2 Q8Figures (i) and (ii) represent intercity highway systems. The black dots represent cities and the…2026 Set 1 Q10An unbiased six-faced dice whose faces are marked with numbers 1, 2, 3, 4, 5, and 6 is rolled twice…2026 Set 2 Q10An unbiased six-faced dice whose faces are marked with numbers 1, 2, 3, 4, 5, and 6 is rolled twice…