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:
475 comments Page 25 of 48.
GwenBiz said:
1 decade ago
@Jothi,
x-5 = 45.
We add 5 to both sides so that we stay with x.
x-5+5 = 45+5.
Therefore,
So x = 50.
x-5 = 45.
We add 5 to both sides so that we stay with x.
x-5+5 = 45+5.
Therefore,
So x = 50.
Sai said:
1 decade ago
This concept is relative to distance not to time so you cannot take a relation like you have mentioned.
Stark said:
1 decade ago
Correct your equation to 125/v1-(10*5)/(5*18) = 10 you will get.
v1 = 13.88 m/s.
==> v1 = 50 kmph.
v1 = 13.88 m/s.
==> v1 = 50 kmph.
Sonali said:
6 years ago
If only one of the speed is given then how will we consider that which one is to be subtracted or not?
Kannips said:
1 decade ago
speed=distance/time.so speed=125/10.....25/2*18/5=45... the question is same direction=x-5=45 x=50
Anish said:
1 decade ago
Hi Manishkumar,Vijaykumarkuppani,Umesh
U hav cleard the points exactly how itz done.
Thanks a lot...
U hav cleard the points exactly how itz done.
Thanks a lot...
Dinesh kumar said:
5 years ago
The speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr.
Please explain it, friends.
Please explain it, friends.
Eric said:
1 decade ago
@Shafi.
This method is quite simple and explain the whole concept, thanks for the nice explanation.
This method is quite simple and explain the whole concept, thanks for the nice explanation.
Robi said:
7 years ago
@Omkar Tanpure.
What is the relative speed? And why 45 is called relative speed? Please explain me.
What is the relative speed? And why 45 is called relative speed? Please explain me.
Muhammad Zulafqar said:
7 years ago
The simplest answer is;
10sec/1000Meter =0.01.
Then multiply with 5KM i.e 0.01 * 5000meter = 50KM.
10sec/1000Meter =0.01.
Then multiply with 5KM i.e 0.01 * 5000meter = 50KM.
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