Multiple choice

Two trains A and B having the lengths 195 m and 165 m, respectively, are running in the same direction on parallel lines. If the speed of A and B be 77 km/h and 85 km/h, respectively, what will be the time (in seconds) taken by them to cross each other?

  1. 162

  2. 164

  3. 160

  4. 166
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A Correct answer
Explanation

Relative speed = 85 - 77 = 8 km/h = 8 * (5/18) m/s = 40/18 = 20/9 m/s. Total distance = 195 + 165 = 360 m. Time = 360 / (20/9) = 360 * 9 / 20 = 18 * 9 = 162 seconds.

AI explanation

Using the relative speed formula for same direction movement, the speed difference is 85 km/hr minus 77 km/hr, yielding 8 km/hr. Converting to m/s gives 20/9 m/s. The total distance to cross is the sum of the lengths, 195 m plus 165 m, yielding 360 m. The time equals distance divided by speed, 360 divided by 20/9, which gives 162 seconds.

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