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:
494 comments Page 50 of 50.
Md shahrukh Ansari said:
3 months ago
Good Explanation. Thanks a lot.
(3)
DHANASURIYA M G said:
2 months ago
Convert the man's speed to meters per second: 5km/hr = 5 × 10003600 ≈ 1.39m/s.
The train covers its length (125 m) in 10 seconds, so its speed relative to the man is 125m/10s = 12.5m/s.
Therefore, the speed of the train is;
12.5 m/s + 1.39 m/s ≈ 13.89 m/s.
which is converted to 50 km/hr.
The train covers its length (125 m) in 10 seconds, so its speed relative to the man is 125m/10s = 12.5m/s.
Therefore, the speed of the train is;
12.5 m/s + 1.39 m/s ≈ 13.89 m/s.
which is converted to 50 km/hr.
(13)
Ravi prasad said:
2 months ago
Relative speed = x - 5.
Formula:
Relative speed = Distance/time.
(x-5) 5/18 = 125/10.
X = (12. 5x18/5) + 5.
= 45 + 5 = 50km/hr.
Formula:
Relative speed = Distance/time.
(x-5) 5/18 = 125/10.
X = (12. 5x18/5) + 5.
= 45 + 5 = 50km/hr.
(16)
Bhanu Pratap said:
1 month ago
The speed of the train is x.
And the speed of the men in m/sec = 5 * 5/18.
= 25/18 m/sec.
So, time = distance/speed.
10 = 125/x-25/18.
10x - 250/18 = 125.
10x - 125/9=125.
10x = 125+125/9.
10x = 1250/9.
x = 1250/90.
x = 125/9.
The speed of the train is 125/9 m/sec.
Converting to km/hr, we get 125/9 * 18/5.
= 50 km/hr.
And the speed of the men in m/sec = 5 * 5/18.
= 25/18 m/sec.
So, time = distance/speed.
10 = 125/x-25/18.
10x - 250/18 = 125.
10x - 125/9=125.
10x = 125+125/9.
10x = 1250/9.
x = 1250/90.
x = 125/9.
The speed of the train is 125/9 m/sec.
Converting to km/hr, we get 125/9 * 18/5.
= 50 km/hr.
(4)
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