Chon goc toa do tai thanh pho HCM goc thoi gian la luc 6hphuong trinh chuyen dong cua
Hong $x_1=48t$
Huong $x_2=72(t-\frac12)$
Huong gap hong khi $x_1=x_2\rightarrow t=1,5$
1,Vay sau 1h30' Huong doi kip hong
2,Tai vi tri gap nhau $x_1=72km$
vay huong hong gap nhau tai vi tri cach Tien Giang $150-72=78km$
3,Voi pt chuyen dong la $x_2=72(t-\frac12)$ thoi gian Huong den Tien Giang la $t_1= \frac{31}{12}h$
Voi Van Tocs $v=48km/h$ Hong di tu TPHCM den Tien Giang can thoi gian la $t_2=\frac{25}8$ h
Hai nguoi den tien Giang cung mot luc suy ra Hong di truoc Huong$\frac{13}{24}h=32$phut30s
Vay Hong di luc 5h57'30"