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 33 of 48.
Angel said:
8 years ago
@Bala.
Speed=(Distance/Time).
Here distance is the length of the train which is 125 m and the time is 10 s
speed=125/10.
Speed=(Distance/Time).
Here distance is the length of the train which is 125 m and the time is 10 s
speed=125/10.
Ashis said:
8 years ago
5 km/h convert into m/s =5*1000/3600 or 5*5/18 =1.38,
Distance traveled by man in 10 sec = 1.38*10=13.8,
Total distance traveling by train =125m +13.8m =138.8,
Final speed of train in 10 sec = 13.88m/s=49.968km/h.
Some error because of 1.38 is approximate.
Distance traveled by man in 10 sec = 1.38*10=13.8,
Total distance traveling by train =125m +13.8m =138.8,
Final speed of train in 10 sec = 13.88m/s=49.968km/h.
Some error because of 1.38 is approximate.
Chithra said:
8 years ago
1 km = 1000 meters.
1 hr = 3600 seconds.
1 km/hr = 1000/3600 m/s.
= 10/36 m/s.
= 5/18 m/s.
Therefore 1 km/hr = 5/18 m/sec.
Similarly, the reciprocal of m/sec is used to calculate km/hr.
1 hr = 3600 seconds.
1 km/hr = 1000/3600 m/s.
= 10/36 m/s.
= 5/18 m/s.
Therefore 1 km/hr = 5/18 m/sec.
Similarly, the reciprocal of m/sec is used to calculate km/hr.
Priya said:
8 years ago
As both the man and train are moving in the same direction than why the relative is subtracted by 5 i.e, x-5 it should be x+5?
Yuvraj said:
8 years ago
Speed=Distance(length of train)/Time;
s=125/10;
But s is (speed of train and man together i.e man's speed is 5km/hr so convert 5*(5/18)& train and man going in same direction that's why -X (let the speed of train)
(X*(5/18))-(5*(5/18))=125/10,
x-5=45,
x=50.
s=125/10;
But s is (speed of train and man together i.e man's speed is 5km/hr so convert 5*(5/18)& train and man going in same direction that's why -X (let the speed of train)
(X*(5/18))-(5*(5/18))=125/10,
x-5=45,
x=50.
Mustufa said:
8 years ago
As we find train speed pass near to man is 45 km/hr and man also running at speed of 5 km/hr so we add train speed with man speed so we get the exact speed of train.
Vasu erothi said:
8 years ago
a km/hr to m/s conversion.
a km/hr =[a*5/18]m/s.
a km/hr =[a*5/18]m/s.
Arup said:
8 years ago
What is 18/5?
Please explain.
Please explain.
Nivetha said:
8 years ago
What is the meaning of (x-5) then, x-5=45?
Please explain this line.
Please explain this line.
Gilbert said:
8 years ago
I think, 18/5 is seconds per meter not metres per second.
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