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:
487 comments Page 43 of 49.
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:
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
VIMAL said:
2 decades 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
Jeevanantham said:
2 decades ago
How to relative 45 with man running speed. Please explain it any one.
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