Add this formula to the right of your table....

=((C3*0.8)+(E3*0.2))/(($C$9*0.8)+($E$9*0.2))

copy down. When i added up the results for all lines in the 1st table, it came out to 1

This is absoluted for just the 1st table, you will have to adjust the $C$9 etc to accomodate the other tables.