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The length of Lucknow mail is 120m and that of punjab mail is 80 m. These two trains are running in the same direction with velocities of 40 km/h and 50 km/h respectively. The time taken by them to cross each other is ?
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- 8 sec.
- 72 sec.
- 11.5 sec.
- 12.5 sec.
Correct Option: B
Relative speed = 50 - 40 = 10 km/h = 50/18 m/s
∴ Time taken = Sum of length of the trains / Relative speed
= (200/50) x 18 = 72 sec.
