Question

A 100m long train cross a man travelling at 5km/hrs in opposite direction in 7.2sec then the velocity of train

Answer 1

Distance to be covered to cross the man = length of train = 100m

Time taken to cross = 7.2s

Relative velocity of train wrt to man = 100/7.2 = 125/9 m/s

Velocity of man = 5kmph = 5×5/18 = 25/18 m/s

Velocity of train = 125/9 - 25/18 = 225/18 m/s = 225/18 × 18/5 = 45 km/h

Answer 2

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Distance to be covered to cross the man = length of train = 100m

Time taken to cross = 7.2s

Relative velocity of train wrt to man = 100/7.2 = 125/9 m/s

Velocity of man = 5kmph = 5×5/18 = 25/18 m/s

Velocity of train = 125/9 - 25/18 = 225/18 m/s = 225/18 × 18/5 = 45 km/h