Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 2)
2.
A train 125 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is:
45 km/hr
50 km/hr
54 km/hr
55 km/hr
Answer: Option
Explanation:

Speed of the train relative to man = 125 m/sec
10

   = 25 m/sec.
2

   = 25 x 18 km/hr
2 5

   = 45 km/hr.

Let the speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr.

x - 5 = 45         x = 50 km/hr.

Discussion:
487 comments Page 28 of 49.

Nish said:   1 decade ago
When we convert km/h to m/sec in that situation we multiple 5/18 and same opposition 18/5.

Jansi said:   1 decade ago
Could you explain how to calculate downstream in still water with example?

Suman said:   1 decade ago
Here given that (x-5) km/hr. What is 5? Please explain.

Sohail said:   1 decade ago
Why did you put 18/5 instead 5/18?

Where 5 denotes the meter and 18 denotes the hours (1000/3600) this should be as (25/2 x 5/18)?

I am a little unclear.

Velu said:   1 decade ago
Here they are asking the train speed. But why we are finding the relative speed.

Deepak said:   1 decade ago
How we where we divide and multiply by 5 and 18?

Abid said:   1 decade ago
How to calculate what Km/Hr is train running if its length is 130 m and cross it own start point in 15 seconds?

PPRakshit said:   1 decade ago
Speed of the train relative to man = 125/10.

How they wrote it?

MammuChowdary said:   1 decade ago
Moving in same direction : SUBTRACT.

Moving in opposite direction : ADD.

SHYAM said:   1 decade ago
Can anyone please explain me why it is divided by 18/5 in place of 5/18?

Reason is 1 km/hr = 1000 m/3600 sec = 10/36 = 5/18.

So why it is used 18/5 in place of 5/18?

Please help me understand?


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