hai xe xuat phat cung luc tai hai diem A,B cach nhau 120km.Xe mot chay voi toc do 30km/h.Xe hai chay ve xe mot voi toc do 54km/h
a)toc do xe ao lon hon va lon hon bao nhieu lan
b)sau bao lau tu luc xuat phat hai xe co the gap nhau tren duong
giai ho minh voi cac ban
cam on cac ban nhieu