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 21 of 48.
Karthik said:
1 decade ago
125/10 = 25/2
25/2*18/5 = 450/10
45
friends,
i don't know how to solve this problems after this
so plz anyone help me out
25/2*18/5 = 450/10
45
friends,
i don't know how to solve this problems after this
so plz anyone help me out
Vijaya said:
1 decade ago
Hi amit and Sarah
Here x - 5 = 45
x= 45 + 5 (when minus (-) simble comes from right of = to left of = it will become +.
Here x - 5 = 45
x= 45 + 5 (when minus (-) simble comes from right of = to left of = it will become +.
Priya said:
8 years ago
As both the man and train are moving in the same direction than why the relative is subtracted by 5 i.e, x-5 it should be x+5?
K.C.Yogannal said:
1 decade ago
@Vijayagopal.
As speed =length/time they have done 125/10. Where 125 is the length and 10 is the time. Hope you understood.
As speed =length/time they have done 125/10. Where 125 is the length and 10 is the time. Hope you understood.
Gowthami said:
1 decade ago
Nice explanation from you frnds but ravi said that we had add that relative speed, I can't understand from his point of view.
Harish said:
1 decade ago
It is brain storming and conceptual question .Thank you for giving more explanation on this question.Thank you very much....!
Mohit kumar said:
1 decade ago
1 km = 1000 m/1 hr = 3600 sec = 5/18 but we want to convert just opposite.
So numerator and denominator will be interchange.
So numerator and denominator will be interchange.
Deepak said:
1 decade ago
In first problem you mentioned that meters per sec is equal to 5/18 but then you are taking like 18/5 why so please tell me.
Nishant said:
8 years ago
But it should have been given that we have to find the relative velocity of the man. So, 45km/hr should be the right answer.
Iliyas said:
3 years ago
m/sec = [1/1000 km] / [1/3600 sec]
= [1/1000] *[3600/1],
= [3600/1000].
= [18/5]km/hr.
= [1/1000] *[3600/1],
= [3600/1000].
= [18/5]km/hr.
(28)
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