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Two trains, of same length, are running on parallel tracks in the same direction with speed 60 km/hour and 90 km/hour respectively. The latter completely crosses the former in 30 seconds. The length of each train (in metres) is
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- 125
- 150
- 100
- 115
Correct Option: A
When two trains cross each other, they cover distance equal to the sum of their length with relative speed.
Let length of each train = x metre
Relative speed = 90 – 60
= 30 kmph
| = |  |  | m/sec. | |
| 18 |
| = | | | m/sec. | |
| 3 |
| ∴ | = 30 | |||||
| 3 | ||||||
| ⇒ 2x = | |
| 3 |
⇒ 2x = 250
⇒ x = 125 metres
