so ket mot tuan hoc 3 to cua lop 6a dat duoc nhieu diem gioi neu lay 1/5 so diem gioi cua to 1 chia deu cho 2 to kia thi so diem gioi cua 3 to bang nhau neu to 1 duoc them 8 diem gioi nua thi so diem gioi cua to 1 bang tong so diem gioi cua 2 to kia hoi moi to duoc bao nhoieu diem gioi