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 8 of 48.

Ragavan said:   1 decade ago
As from the problem. two contrain have to remember
*If the man moving towards train. so that train pass the man faster then speed so add the distance.
*If not move towards train. The train pass the man late.so minus the distance

Arul said:   1 decade ago
Hey the quesion is about the speed of the train. jjust bcoz aman runs... will the speed of the train increase...? a little help here pls...

Salahuddin said:   1 decade ago
To avoid confusion

Simple convert the trains speed for 1 hr - metres/seconds, 125m/10 sec. So 125 * 6 * 60 / 10 * 6 * 60 = 45000 mtrs/ 3600 . So to convert it, divide by 1000, its 45 kms/hr.

As the man running in the same direction at a speed of 5kms/hr add 45 + 5, if the person moves in opposite direction then subtract. Just logic guys

Kaushik Rathod said:   1 decade ago
Answer in Another way :-

Speed = 5*18/5 = 18 km/hr
Time = 10 sec.
X + 125 / 10 = 18
X + 125 = 180
X = 180-125
X=55

Now, Speed = X-5
So , Speed = 55 - 5
Speed = 50 km/hr

Ajith said:   1 decade ago
So in the above problem let us consider that the speed of the person is 5 km\hr .

Leave the 5 as it is and then convert the km\hr into m\s
that means 1 km=1000m
and 60min=3600sec

Now when actually converted 3600\1000 that would give u the two zero gets cut and remains is 36\10 that would give u after dividing each by 2 i.e 18\5which means
(18m\5s)1.FRACTION

Now the major calculation,
Two object over here is Train and the Man consider them as A and B
where A is the Train as we have to find the speed of the train
then B is the speed of the Man is 5
so we get A-5

We had 125m the length of train time 10 seconds
already these are in meters and in seconds no need to convert them so 125m\10s u get (25m\2sec) 2.FRACTION

Now, finally get the first fraction and the second fraction together i.e (18\5)*(25\2)u get 45 as answer when u calculate
then A-5=45 ,when u move the negative -5 to this side of the equals too sign it converts to positive giving u A=45+5

i.e 50 so A=50 and A is the speed of train!!hope u'll understood!!take care!!
(3)

Monisha said:   1 decade ago
Great job guys!!! I understood well than my faculty teaches...

Raja said:   1 decade ago
Thank you friends I understood well never before.

Every one has given their own ideology with respect to problem.

Umesh said:   1 decade ago
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:

====> dist. travelled by man in 10 sec. = (5*5/18) *10=250/18
A train will have to travel its own length + dist.travelled by man. (when train will pass the man he would have travelled 125/9 m in same dir.)

i.e. 125+125/9 meters = 1250/9
speed of train = (1250/9)/10 = 125/9 m/s=125/9 *18/5 = 50 km/hr

Tarun dumra said:   1 decade ago
Nice expalnation by ankita.

Vandna said:   1 decade ago
Can anyone solve this?

A train moving at 36Kmph takes 12 seconds to cross a platform. It takes 6 seconds to cross a man running at the rate of 9Kmph in the opposite direction. Find the length of the train.


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