A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Though you have set your drop down list as "Yes" or "No", then you can use the below simple formula:
In E27:
=IFERROR(IF(E25="no",0,F27/G27),"")
in F27 to calculate several cells, try the below formula:
=SUM(single_cell1,single_cell2,.......,cell_range1,cell_range2,....)
in G27 to calculate the G column, try below formula:
=SUM(G:G)