thua ruong thu nhat co dien tich kem hon thua ruong thu hai la 120 m .dien tich thua ruong thu nhat = 2/5 thua ruong thu hai. ngtuoi ta cay lua o hai thua ruong.trung binh 100 m thi thu hoach duoc 75 kg thoc , hoi ca hai thua ruong thu hoach duoc bao nhieu ta thoc