Question

Two trains start from the same station at $11.p.m$ in opposite direction at speeds of $72km/h$ and $63km/h$, respectively. At what time they will be $810km$ apart?

Answer 1

Consider the following question.

$Time=\frac{RelativeDistanc}{RelativeVelocity}$

$=\frac{\left(810km\right)}{(72kmph+63kmph)}$

$=6hours$

They’ll be $810km$from start.$6hr$

In other words, they’ll be $810km$ apart at $05:00PM$

Hence, this is the required answer.