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 13 of 48.
Meera said:
1 decade ago
Thanks mr. Suganthan. Its really very nice to understand thanks:) ) ).
Shashank said:
1 decade ago
Hi. Please tell me why x-5 ?
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.
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.
Washeru said:
1 decade ago
Good expl. frm Rahuul
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
*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
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
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
Monisha said:
1 decade ago
Great job guys!!! I understood well than my faculty teaches...
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