mot truong tieu hoc muon lat lai nen cac phong hoc . nguoi ta tinh rang co 7 phong hoc can lat lai nen , moi phong deu co dien tich nen la 40 m2 va chi dung toan loai gach vuong co do dai moi canh la 40 cm . hoi can it nhat bao nhieu vien gach hoa cung loai thi lat du cac phong hoc da du dinh coi dien tich mach vua khong dang ke