Question

And train 135 metre long is running with a speed of 49 kilometre per hour in what time will it pass away boy who is walking at 5 kilometre per hour in the direction opposite to that of the train? ​

Answer 1

$\:\: \underline{\underline{\bf{\large\mathfrak{~~Solution~~}}}}$

l=135m=0.135km

v(train)=49km/hr

v(boy)=5km/hr

now as they are moving in the opposite direction to each other so...

the relative velocity of the train is

=49+5=54km/hr

now time taken by the train is ...

$= \frac{0.135}{54} hrs \\ = \frac{1}{400} hrs \\ = 9 \: \: sec$