Discussion of Question with ID = 070 under Problems-on-Trains

This is the discussion forum for this question. If you find any mistakes in the solution, or if you have a better solution, then this is the right place to discuss. A healthy discussion helps all of us, so you are requested to be polite and soft, even if you disagree with the views of others. The question and its current solution has also been given on this page.



Two trains moving in the same direction, and running respectively at 36km/h and 72km/h cross each other in 7sec. What is the length of each train if the two trains are equally long?


35 m.


36 m.


34 m.


37 m.

Ans: a

The trains cover a distance equal to the sum of their lengths at a relative speed 72 - 36 = 36km/h × (5/18), or 10m/s. We can use the speed distance formula: sum of lengths = 10 × 7 = 70m. Halving this we get the length of one train = 35m.

Comments and Discussion