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:
478 comments Page 42 of 48.
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:
1 decade ago
Hi. Please tell me why x-5 ?
Meera said:
1 decade ago
Thanks mr. Suganthan. Its really very nice to understand thanks:) ) ).
Jitendra Prajapati said:
1 decade ago
Very good explanation by Suganthan.
Gowthami said:
1 decade 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:
1 decade ago
Thanks frnd. I understand properly.
Suganthan.M said:
1 decade 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:
1 decade ago
Hi I can't understand friends. What is this x-5 ?
Please anyone explain clearly.
Please anyone explain clearly.
Vasuedvareddy said:
1 decade 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
VIMAL said:
1 decade ago
This is good Question i understand that, some friend disturb for 18/5. its simple its unit for km/hr. let see that1km=1000m & 1hr = 3600 second so 1000/3600 = 5/18 . And see that If we want to small unit convert in to big unit we have to divide & if we want to big unit convert in to small we have to multiply so here they dividing and write 18/5 ok so encourage your self my friend go ahead. VIMAL SONI & DUSHYANT SONI
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers