Question

Two trains each of length 100 m moving parallel
towards each other at speed 72 km/h and
36 km/h respectively. In how much time will they
cross each other?​

Answer 1

SoluTion :-

$\sf {Both\ the\ trains\ are\ of\ length\ 100\ m}\\\\\\\\\sf {Total\ distance\ will\ be}\sf {\ = 100 + 100}\\\\\\\sf {= 200 m}$

$\sf {Relative\ speeds = 72 + 36}$

$\sf {= 108\ km/h}\\\\\\\sf {= 108\ \times \frac{1000}{ 3600}\ m/s}\\\\\\\sf {= 30 m /s}$

${\boxed {\sf Time = \frac{Distance}{Speed}}}\\\\\\\\\sf {\mapsto \frac{200}{30}}\\\\\\\sf {\mapsto 6.67\ sec}$