Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 11)
11.
A 270 metres long train running at the speed of 120 kmph crosses another train running in opposite direction at the speed of 80 kmph in 9 seconds. What is the length of the other train?
Answer: Option
Explanation:
Relative speed = (120 + 80) km/hr
| = |  |
200 x | 5 |  m/sec |
| 18 |
| = | |
500 | m/sec. |
| 9 |
Let the length of the other train be x metres.
| Then, | x + 270 | = | 500 |
| 9 | 9 |
x + 270 = 500
x = 230.
Discussion:
66 comments Page 7 of 7.
Kumaresan.P said:
1 decade ago
Hi friends please help me,
How to identify relative speed and average speed and normal train problems?
How to identify relative speed and average speed and normal train problems?
Ajit said:
1 decade ago
Use the formula, t = a+b/u+v, (train running opposite direction).
Where t = First train passes other train in time.
a+b = Length of train.
u = Speed of first train and v=speed of second train.
Then, 9 = 270+b/(120+80) km/hr.
<=> 270+b = 200 km/hr*9s = 500 m.
Now, b = 500-270 = 230 m.
Where t = First train passes other train in time.
a+b = Length of train.
u = Speed of first train and v=speed of second train.
Then, 9 = 270+b/(120+80) km/hr.
<=> 270+b = 200 km/hr*9s = 500 m.
Now, b = 500-270 = 230 m.
Sindhu said:
1 decade ago
Why we writing denominator 9 for x+270?
Prasad said:
1 decade ago
How this 5/18 came? Can you solve this ?
Manish said:
1 decade ago
Why there you take x+270/9?
Silambuiks said:
1 decade ago
@Prasath.
5/18 means.
1 km = 1000 meter and 1hr = 3600 second.
Convert Kilometer per hour into Meter per second.
Divide the value of 1000/3600 its answer is 5/18.
5/18 means.
1 km = 1000 meter and 1hr = 3600 second.
Convert Kilometer per hour into Meter per second.
Divide the value of 1000/3600 its answer is 5/18.
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