. Two trains 140m and 160m long run at the speed of 60km/hr


and 40km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other is

A: 9

B: 9.6

C: 10

D: 10.8

 

Best Answer

Explanation:

When two bodies move in opposite direction, then the Relative Speed = Sum of Speeds

Relative speed =(60+40)km/hr

=100km/hr

=100 ×18 /5m /sec

=250 /9m /sec

Distance covered by the trains in crossing each other =(140+160)km=300km

Required time =Distance /Speed

=300 /250 ×9

=10.8sec

Final Answer:

Hence, the correct option is D i.e. 10.8

 

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