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 6 of 7.
Aswin said:
1 decade ago
Please let me know, where 100/3 comes from?
Amudha said:
1 decade ago
To find length of one train why we are calculating relative speed?
Amar said:
1 decade ago
kmph means kilometer per hour(Km/h).
Krishna said:
1 decade ago
The speed & time of the other so we can directly get the length of the other train.
Kadoliya jitendra said:
1 decade ago
What is kmph?
Sushma said:
1 decade ago
As given: 120+80=200
200*5/18=500/9
Let the length of other train be X
then X+270/9=500/9
cross multiply, u vl get
9X + 2430= 4500
9X=2070.
.'. X=2070/9
x=230
200*5/18=500/9
Let the length of other train be X
then X+270/9=500/9
cross multiply, u vl get
9X + 2430= 4500
9X=2070.
.'. X=2070/9
x=230
Kpkpkp said:
1 decade ago
When two trains move in opp direction you cant add length. Because length of smallest train is common to both. The actual distance travelled will be length of large train only.
Pramod said:
1 decade ago
Two trains are in opposite travelling in the opposite direction. So how can can add their length? It has to be be subtraction. If they are moving in the same direction then add only.
Nareen said:
1 decade ago
Short cut Method
Relative speed = (120 + 80) km/hr
= 200 x 5/18 m/sec
= 500/9 m/sec.
= 500/9*9
= 500 m
= u+v = 500
= 270+v = 500
= 230m
Relative speed = (120 + 80) km/hr
= 200 x 5/18 m/sec
= 500/9 m/sec.
= 500/9*9
= 500 m
= u+v = 500
= 270+v = 500
= 230m
Yogesh said:
1 decade ago
Pleas let me know, where 100/3 comes from ?
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