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:
475 comments Page 11 of 48.

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 .........!

Amit said:   1 decade ago
Hi friend's
Hey ravi nice explanation.

Manishkumar said:   1 decade ago
@ all apply logic don't simply go for routine

speed of man is 5km/hr and in mt/sec is 1.39.
so total distance covered by main in 10 sec is 13.9 m
so total distance covered by train in 10 sec is 125+13.9=138.9
so total distance covered by train in 1 sec is 13.89m
and if we convert this in km/hr
i.e. 13.89*3600/1000= 50km/hr

Ravi U S said:   1 decade ago
Thanks Amit


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