Co hai cai can , 1 cai loai 20 lit , 1cai loai 10 lit trong mi can dung 1 luong dau .Neu do tu can 20 lit sang can 10 lit cho day , thi can 20 lit chi het 1/8 so dau luc dau dung trong can 20 lit . Neu do dau tu can 10lit sang can 20lit cho day thi trong can nho con lai 4lit dau . Hoi luc dau moi can dung bao nhieu lit?
xin loi vi ko the danh dau thanh
