20 gaini + 7 gaste = 1878 kg
30 gaini + 7 gaste =2558 kg => 7 gaste =2558 -30 gaini
20 gaini + 7 gaste =1878
20 gaini + 2558 -30 gaini =1878
-10 gaini +2558 =1878
2558 -1878 =10 gaini
680 =10 gaini
1 gaina =68 kg graunte
7 gaste =2558 -30 gaini
7 gaste =2558 -2040
7 gaste =518
1 gasca = 74 kg graunte