Find the time taken by a train 150 m long running at a speed of 63 kmph to cross another train of length 100 m long running at a speed of 45 kmph in the same direction

50 seconds

Speed = \(\frac{ Distance}{ Time}\)

Speed of 1st train in m/s = 63 x \(\frac{5 }{ 18}\) = \(\frac{35 }{ 2}\) m/s

Speed of 2nd train in m/s = 45 x \(\frac{5 }{ 18}\) = \(\frac{25 }{ 2}\) m/s

So, putting values in the formulae:

Speed = \(\frac{ Distance}{ Time}\)

\(\frac{35 }{ 2}\) - \(\frac{25 }{ 2}\) = \(\frac{\text{150 + 100}}{ Time}\)

\(\frac{10 }{ 2}\) = \(\frac{\text{150 + 100}}{ Time}\)

Time = \(\frac{\text{250}}{ 5}\)

Time = 50 seconds