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:
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:
489 comments Page 43 of 49.
Dhandapani said:
1 decade ago
Simple you can multiply 5*10.
5-a man running 5km/hr and the train reached in 10 seconds.
5*10=50km/hr.
5-a man running 5km/hr and the train reached in 10 seconds.
5*10=50km/hr.
Binod verma said:
1 decade ago
When two things are running in the same direction or opposite direction then we say that motion is in relative between them. So at first we find the relative motion and then find the speed of train.
If someone want to find out speed of man that are given in the question.
If someone want to find out speed of man that are given in the question.
Shashank said:
2 decades ago
Hi. Please tell me why x-5 ?
Meera said:
2 decades ago
Thanks mr. Suganthan. Its really very nice to understand thanks:) ) ).
Jitendra Prajapati said:
2 decades ago
Very good explanation by Suganthan.
Gowthami said:
2 decades ago
Nice explanation from you frnds but ravi said that we had add that relative speed, I can't understand from his point of view.
Chetana said:
2 decades ago
Thanks frnd. I understand properly.
Suganthan.M said:
2 decades ago
We need the speed of the train
we have only one clue about the train is 125m and 10s
speed=distance/time
(i.e)125/10= 12.5 m/s
but we need the answer in km/hr so convert it
12.5*(18/5)=12.5*3.6
=45 km/hr almost we got it
then about the direction, it is in same direction
Now the speed of the train as x,
because of same direction subtract it from x
x-5=45
x=45+5
x=50km/hr
we have only one clue about the train is 125m and 10s
speed=distance/time
(i.e)125/10= 12.5 m/s
but we need the answer in km/hr so convert it
12.5*(18/5)=12.5*3.6
=45 km/hr almost we got it
then about the direction, it is in same direction
Now the speed of the train as x,
because of same direction subtract it from x
x-5=45
x=45+5
x=50km/hr
Sarah said:
2 decades ago
Hi I can't understand friends. What is this x-5 ?
Please anyone explain clearly.
Please anyone explain clearly.
Vasuedvareddy said:
2 decades ago
@Vasudeva reddy
1km = 1000m =100,000cm
1 inch = 2.54cm
1 ft=12 inches = (12*2.54)cm
1km = 0.621371192 mile
1.609344 km = 1 mile
1km = 1000m =100,000cm
1 inch = 2.54cm
1 ft=12 inches = (12*2.54)cm
1km = 0.621371192 mile
1.609344 km = 1 mile
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