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:
478 comments Page 11 of 48.

Mozammel hossain said:   7 years ago
There have man speed but not train speed.

So we known that;
speed = distanc/time.

= 125/10,
= 25/2.

Now convert into km/h.
25/2 * 18/5.
= 45km/h.

Lets train speed is x km/h.
So, the relative speed is x-5 km/h.
x- 5 = 45,
X = 50km/h.

Nithish said:   7 years ago
Thanks all for the explanations.

Muhammad Zulafqar said:   7 years ago
The simplest answer is;

10sec/1000Meter =0.01.
Then multiply with 5KM i.e 0.01 * 5000meter = 50KM.

Vinod said:   7 years ago
Thanks all for explaining the answer.

Anjali said:   7 years ago
Thanks all for explaining the answer.

Abuthahir said:   7 years ago
X-5 = 45.
Here x = 45+5,
Then x = 50.

Narendra said:   7 years ago
In same direction, T. S-M. S = 125/10 * 18/5 = 45.
M.S = 5KMph.
T.S - 5 = 45.
T.S = 50sec.

Lavanya said:   7 years ago
Why do we to subtract 45-5? please clarify that.

Hari kumar said:   7 years ago
50 is the right answer.

Chandan Azad said:   7 years ago
T(time required) = Lt(length of train) + Lo(length of object)/ Ut(speed of Train)+,-Uo(speed of object) .
("-" when train and object goes in same direction.
"+" when train and object goes in opposite direction.)

10=(125+0)/(Ut-5*5/18).
Ut=125/9.
Ut=(125/9)*(18/5).
Ut=50km/hr.


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