1 votes 1 votes my doubt is why 14 has been subtracted ?? Manis asked Feb 1, 2018 Manis 256 views answer comment Share Follow See all 2 Comments See all 2 2 Comments reply Ajay Jadhav commented Feb 1, 2018 reply Follow Share Spanning tree has 4 edges therefore,7C4=35 But there might be cycles of length 4 or 3,we have to calculate those first 4 length cycles, ABCD,BCDE -->2 3 length cycles ABC remaining edge choices 4(BE,BD,DE,CD) BCD,4 edge choices, BDE,4 edge choices so 4+4+4+2=14 combinations have cycle. 35-14=21 0 votes 0 votes Manis commented Feb 1, 2018 reply Follow Share Thanks brother... 0 votes 0 votes Please log in or register to add a comment.