Two trains of lengths 100 m and 150 m are moving in opposite directions at 40 km/h and 60 km/h, respectively. Find the time taken by the trains (in seconds) to cross each other other.
9 seconds
Relative speed (opposite directions): \(40+60 = 100\) km/h \(= 100\times\tfrac{5}{18} = \tfrac{250}{9}\) m/s.
Combined length: \(100+150 = 250\) m.
Time to cross: \(\dfrac{250}{250/9} = 9\) seconds.
Hence, the trains take 9 seconds to cross each other.
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