mot khoi go hinh hop chu nhat co chieu dai 14 cm , chieu rong 10 cm , chieu cao 6 cm duoc son 6 mat . nguoi ta cua khuc go thanh 105 khoi lap phuong co canh 2 cm . Vay co :
a) ......khoi lap phuong duoc son 3 mat
b ) ....... khoi lap phuong duoc son 2 mat
c)......khoi lap phuong duoc son 1 mat
d)......khoi lap phuong khong duoc son mat nao ?