Question

Two cars leave from the same place at the same time and travel in opposite direction.
One car travel at a constant velocity of 55 km/h and the other at 75 km/h. After how many
hours will there be 520 km apart?

Answer 1

Gives

$V_1=55km/h \\ V_2=75km/h\\s=520km\\$

Both moue opposite direction

Then relatively velocity

$$V=V_1+V_2=55km/h+75Km/h=130km/h$$

Times

$t=\frac{S}{V_1+V_2}=\frac{520}{130}=4h$