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# D1 Help watch

1. Hello

Can someone help me with this question please. THANKS!!!!

A connected graph G has five vertices and has eight edges with lengths 8, 10, 10, 11, 13, 17,
17 and 18.
(a) Find the minimum length of a minimum spanning tree for G. (2 marks)
(b) Find the maximum length of a minimum spanning tree for G. (2 marks)
(c) Draw a sketch to show a possible graph G when the length of the minimum spanning
tree is 53.
2. I don't think we can help you unless you post the graph. If there is one.
3. Are you given any information about the how the graph looks? becuase i think it would be pretty hard to find a minimum spanning tree otherwise - unless you just add up the 4 shortest edges
4. (Original post by chronicl3)
Hello

Can someone help me with this question please. THANKS!!!!

A connected graph G has five vertices and has eight edges with lengths 8, 10, 10, 11, 13, 17,
17 and 18.
(a) Find the minimum length of a minimum spanning tree for G. (2 marks)
(b) Find the maximum length of a minimum spanning tree for G. (2 marks)
(c) Draw a sketch to show a possible graph G when the length of the minimum spanning
tree is 53.
(a)(b)A minimum spanning tree always has 1 less edge than there are vertices.
There are 5 vertices in this graph, so the minimum spanning tree would have 4 edges. Find the min/max length of 4 edges from the lengths given.
5. (c) Find 4 edges that have a total length of 53 and draw a tree with them and all the vertices. Then add the other edges onto the graph however you like.
6. (Original post by Bhups)
Are you given any information about the how the graph looks? becuase i think it would be pretty hard to find a minimum spanning tree otherwise - unless you just add up the 5 shortest edges
There is no graph unfortunately
7. (Original post by chronicl3)
There is no graph unfortunately
You have been given 5 vertices and 8 edges - you have to make your graph from these
8. (Original post by starofale)
You have been given 5 vertices and 8 edges - you have to make your graph from these

9. I posted about parts a and b together earlier on
b is just the same as a but you have to find the maximum lengths to make the tree
10. This was in my actual D1 exam AQA D1 Jan 09
11. (Original post by starofale)
I posted about parts a and b together earlier on
b is just the same as a but you have to find the maximum lengths to make the tree

very confused.

In the markscheme, it says the maximum = 8+17+17+18. But I dont understand why they used 8 instead of 13.

12. (Original post by chronicl3)
very confused.

In the markscheme, it says the maximum = 8+17+17+18. But I dont understand why they used 8 instead of 13.

hmm... I would have thought it would be 13. I'm not sure why they put 8.

Was that the full question you posted, or was there any extra information?
13. (Original post by starofale)
hmm... I would have thought it would be 13. I'm not sure why they put 8.

Was that the full question you posted, or was there any extra information?
That was the full question
14. (Original post by chronicl3)
That was the full question
Well I'm not sure why they didn't use 13. Anyone have any ideas?

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