Question
A person is jogging at 10 m/sec in the same direction of
a train. The train crosses him in 6 seconds. If the speed of the train is 90 km/hr, find the time it takes to cross a tunnel of 60 metres.Solution
Train speed = 90 × (5/18) = 25 m/sec
Relative speed = 25 - 10 = 15 m/sec
L / 15 = 6 ⇒ L = 90 metres
Time to cross the tunnel = (90 + 60)/25 = 150/25 = 6 seconds
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