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Aptitude Day 285

Problems on Trains: 

1. 2 trains 80 m and 100 m in length are running towards each other on parallel lines, one at the rate of 60 km/hr and another at 42 km/hr. In what time will they be clear of each other from the moment they meet?

Solution:
                  Relative speed = 60-42 = 18 km/hr 
                                                        = 18*5/18 
                                                        = 5 m/s.

                  Length = 80+100 
                              = 180 m.

                  Time = 180/5 
                           = 36 seconds.

2. A train running at the speed of 40 km/hr crosses a pole in 18 seconds. What’s the length of the train?

Solution:
                 Speed = 40km/hr 
                            = 40*5/18
                            = 100/9 m/s.


                  Length = 18*100/9
                              = 200 m.


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