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Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 2)
Problems on Trains
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:
478 comments Page 11 of 48.
Kannips said:   1 decade ago
speed=distance/time.so speed=125/10.....25/2*18/5=45... the question is same direction=x-5=45 x=50
Kumar said:   1 decade ago
Why 125 is divided by 10?
Prithika said:   1 decade ago
@kumar
cause speed=distance/time
Raghu said:   1 decade ago
How it is 3600/1000. It will come as 1000/3600 only. Please explain.
Tahira said:   1 decade ago
Hai fnds.

Howz the 12.5 is converted into 25.

Please explain.
Saranya said:   1 decade ago
hai raghu, in the question man's speed is given in km/hr so we gonna convert train's speed to km/hr which is actually in m/s
1 m/s = 3600 km/1000 hr
125/10 m/s= (125/10)*(3600/1000)
REKHA said:   1 decade ago
Ramesh chandran.

CLEAR explanaTION. THANKS.
Mani said:   1 decade ago
Hi Tahira,

You just cancel 125/10 using multiples of 5.

125/10=25/2=12.5.
SHANMUGA PRIYA.TEX said:   1 decade ago
NICE EXPLANATION ABHISHEK.
Amol said:   1 decade ago
Hi Friend's
Thanks for teaching it really works dude ,
1km=1000m and 1hr =36000 then 5/18 m/sec it's simple.

Thanks for that .........!
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