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Two trains of length 100 m and 200 m are 100 m apart. They start moving towards each other on parallel tracks, at speeds 54 kmph and 72 kmp…

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Two trains of length 100 m and 200 m are 100 m apart. They start moving towards each other on parallel tracks, at speeds 54 kmph and 72 kmph. In how much time will the trains cross each other?

A57/7 sec
B80/7 sec
C20/7 sec
D60/7 sec

Correct answer: B

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Discussion 1

CCommunity12 Jul 2021

80/7 sec

Relative speed = (54 + 72)* 5/18 = 7 * 5 = 35 mps.

The time required = d/s = (100 + 100 + 200)/35

= 400/35 = 80/7 sec.