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:
476 comments Page 20 of 48.
Ankur said:
9 years ago
A train speeds past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:
Kindly solve it with full description.
Kindly solve it with full description.
Bandi Pravalika said:
1 year ago
18/5 is the direct formula to convert the m/seconds to km/hr.
In this given problem, we can convert the m/sec to km/hr so we use 18/5.
In this given problem, we can convert the m/sec to km/hr so we use 18/5.
(14)
Nagapriya said:
1 decade ago
Now I understand that,.
Distance = Speed*Time.
Time = Distance/Speed.
Speed= Distance/Time.
OK guys, very thanks to your teaching.
Distance = Speed*Time.
Time = Distance/Speed.
Speed= Distance/Time.
OK guys, very thanks to your teaching.
Gaurav said:
8 years ago
Hey someone tell me, please. Why are you using 18/5 then 5/18?
Because the unit is m/s = 5/18 and you are using 18/5 in this problem.
Because the unit is m/s = 5/18 and you are using 18/5 in this problem.
Shibin said:
1 decade ago
Relative speed = x-5 (x is the speed of train).
(x-5)*5/18 = 125/10.
x-5 = 125*18/10*5.
x-5 = 125*9/25.
x-5 = 5*9.
x-5 = 45.
x = 50.
(x-5)*5/18 = 125/10.
x-5 = 125*18/10*5.
x-5 = 125*9/25.
x-5 = 5*9.
x-5 = 45.
x = 50.
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
Shashi said:
9 years ago
@Suma
Relative speed comes when we measure speed between any objects moving at a time.
Here man and train are moving at a time.
Relative speed comes when we measure speed between any objects moving at a time.
Here man and train are moving at a time.
Kamalakannan said:
1 decade ago
Answer = 45 km/hr is relative speed of the train.
Now, you calculate (u-v).
The Speed of the train 50 km/hr answer is correct.
Now, you calculate (u-v).
The Speed of the train 50 km/hr answer is correct.
Vaitheesh kumar said:
10 years ago
Guys I have one doubt for finding out the relative speed we should need to subtract but here it's divided please explain me how?
Shailesh Hiremath said:
8 years ago
So, kilometre & minutes will be calculated as 1 km=1000 mtrs and 60 minutes =3600 seconds.
If you divide 3600/1000 = 5/18.
If you divide 3600/1000 = 5/18.
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