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I have a question which i am unable to understand.
Question:A passenger train traveled at a speed of 72 km/h. A man on the passenger train observed a goods train travelling at a speed of 54 km/h in the opposite direction. If the goods train passed him in 8 seconds, find the length of goods train.
Please explain to me how should this question be solved as i have another question like this to solve.
First find relative speed of train = 72 + 54 = 126 km/h
now convert km/h to meters/sec, which would be 1000/3600
so relative speed of train = 126 x (1000/36) m/s
which is 35 m/s
we know that slower train passes man in faster train in 8 seconds, so the length of the slower train = distance it covers in 8 seconds
so that is 35 x 8 = 280 meters
I think that's right anyway. It's quite a common type of time/speed/distance question.