Aptitude Day 297

Answers of Day 296: 1. 16 seconds. 

                                    2. 100 m.

Problems on Trains:

1. 2 trains are running in opposite directions at the same speed. If the length of each train is 150 m and they cross each other in 15 seconds, then the speed of each train is:

Solution:

                  2x = 150/15

                  x = 5 m/s

                 Speed = 5*18/5 

                            = 18 km/hr.

2. 2 trains of equal lengths 10 and 5 seconds respectively to cross a post. If the length of each train be 100m, in what time will they cross each other travelling in opposite direction?

Solution:

                  Speed of the train 1 = 100/10 = 10 m/s.

                  Speed of the train 2 = 100/5 = 20 m/s.

                 Time = (100+100)/(20+10) 

                          = 200/30 

                          = 6.7 seconds.