Spanning Trees of above graph means
- Subgraph of given graph
- It should be edge cover
- It should be a tree
Here tree Contains n-1 Edges =5 Edges
Total edges in the graph=7
Here No of Spanning tree = All possible Subgraphs which contains 5 edges out of 7 edges - 5edged Subgraph but not Spanning tree due to presence of Cycle
So No. Of spanning tree= 7C5 - (3+3)= 21-6=15 is Ans
The following 6 subgraphs are 5-edged but not spanning tree bcz they contain cycle
So Ans is 15