Let F be a forest with 100 vertices and 90 edges. How many new edges must be added without adding vertices to obtain a tree?
This is what I have so far for this question... I don't think it's this simple, but please tell me where I went wrong..
We can link the forests together to make one big tree. A tree on n vertices has n-1 edges, so we need to add 9 more edges (100-1 = 99 and we only have 90 edges) to obtain a tree.