Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 7)
7.
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:
50 m
72 m
80 m
82 m
Answer: Option
Explanation:

Let the length of each train be x metres.

Then, distance covered = 2x metres.

Relative speed = (46 - 36) km/hr

   = 10 x 5 m/sec
18

   = 25 m/sec
9

2x = 25
36 9

2x = 100

x = 50.

Discussion:
232 comments Page 7 of 24.

Tintu said:   1 decade ago
Cant we do like:
relatv speed=10km/hr
Time=36 sec=.6hr
Then 2x distance is given by 10*.6 hours=6hrs
So x=3hrs

Anne87 said:   1 decade ago
Good day! I just want to know why you used 2X/36? why did you used 36? Thank you!

Taj said:   1 decade ago
Please clarify my doubts.

How it is possible ? 50 m.

Srikanth said:   1 decade ago
@Taj.

You just go through the Train formulas you will get clear idea.

Rammurthy said:   1 decade ago
How this equation: 2x/36 = 25/9?

Pavithra said:   1 decade ago
Why not we take 2x/46 ?

Sid said:   1 decade ago
What is relative speed. Please explain me in somewhat detail manner. Cant understand.

Venkatesh said:   1 decade ago
Thanks jelli.

Venkatesh said:   1 decade ago
Hi jelli, can you give a important equations used in that kind of problems.

Ster said:   1 decade ago
2x as distance only makes sense if the faster train start behind the slower train. If they were right next to each other at the start, the distance traveled would only be x. Question does not clarify this. Please amend.


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