The two cars start from the opposite direction of a and B. the express train is 70km at one time and the local train is 60km at one time. The two cars meet at 20km away from the terminal. How many kilometers is the distance between a and B Accurate and effective

The two cars start from the opposite direction of a and B. the express train is 70km at one time and the local train is 60km at one time. The two cars meet at 20km away from the terminal. How many kilometers is the distance between a and B Accurate and effective

70-60=10(km)
Is it the end or the midpoint?
20*2=40(km)
40 / 10 = 4 (hours)
70*4+60*4
=280+240
=520(km)
If it's the middle point, it's this. If it's the end point, I'm sorry,
A: the distance between a and B is 520km