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Two trains 150 m and 120 m long respectively moving from opposite directions cross each other in 10 secs. If the speed of the second train is 43.2 km/hr, then the speed of the first train is
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- 54 km/hr
- 50 km/hr
- 52 km/hr
- 51 km/hr
Correct Option: A
Speed of second train
= 43.2 kmph
= | m/sec. | |
18 |
or 12 m/sec.Let the speed of first train be x m per second, then
= 10 | |
x + 12 |
⇒ 27 = + x 12
⇒ x = 15 m/s
= 15 × | kmph = 54 kmph | |
5 |