Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 27)
27.
A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. The length of the train is:
Answer: Option
Explanation:
| 2 kmph = |  |
2 x | 5 |  |
m/sec = | 5 | m/sec. |
| 18 | 9 |
| 4 kmph = | |
4 x | 5 | |
m/sec = | 10 | m/sec. |
| 18 | 9 |
Let the length of the train be x metres and its speed by y m/sec.
| Then, |  |
x |  |
= 9 and | |
x | |
= 10. |
|
|
9y - 5 = x and 10(9y - 10) = 9x
9y - x = 5 and 90y - 9x = 100.
On solving, we get: x = 50.
Length of the train is 50 m.
Discussion:
106 comments Page 6 of 11.
Gopal said:
1 decade ago
Here man walking same direction of train because.
Relitive speed = train speed - man spped.
Ok.
Relitive speed = train speed - man spped.
Ok.
Syndhya said:
1 decade ago
@Kapil
Please say why we are taking here why here we taking s-s1 and not s-s2 in your solution.
Please say why we are taking here why here we taking s-s1 and not s-s2 in your solution.
Arsalan said:
4 years ago
Why we have not converted the speed of the train in m/s initially? Anyone explain it, please.
(1)
Ravi said:
1 decade ago
Please any one can simply this step by step x/(y-10/9) = 10.
How can we get 10(9y-10) = 9x?
How can we get 10(9y-10) = 9x?
IDPRASAD said:
8 years ago
4-2=2 speed diff (same direction).
Kmph to mph.
2 * 5/18 = 5/9.
D=s * t
5/9 * 9 * 10 = 50.
Kmph to mph.
2 * 5/18 = 5/9.
D=s * t
5/9 * 9 * 10 = 50.
Divya Bisht said:
7 years ago
Can anyone tell me that why we take 2kmph nd 4kmph separate? Why we not done 4kmph+2kmph?
Vickey pandy said:
5 years ago
Same direction =>2-4=2.
2*(5/18)= 5/9,
D = S*T.
D = (5/9)*10*9,
D = (5/9)*90,
D = 50.
2*(5/18)= 5/9,
D = S*T.
D = (5/9)*10*9,
D = (5/9)*90,
D = 50.
Vinila said:
1 decade ago
In the 1st method.
On solving,
9y - x = 5 and 90y - 9x = 100.
We get: x = 50.
How?
On solving,
9y - x = 5 and 90y - 9x = 100.
We get: x = 50.
How?
Krishna said:
9 years ago
@All.
Please anyone give the answer of Durga's question, I have the same question.
Please anyone give the answer of Durga's question, I have the same question.
Pavi said:
11 months ago
The speed is already given in that question itself so why do you declare that as y?
(2)
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