Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 13)
13.
Two trains, each 100 m long, moving in opposite directions, cross each other in 8 seconds. If one is moving twice as fast the other, then the speed of the faster train is:
Answer: Option
Explanation:
Let the speed of the slower train be x m/sec.
Then, speed of the faster train = 2x m/sec.
Relative speed = (x + 2x) m/sec = 3x m/sec.
 |
(100 + 100) | = 3x |
| 8 |
24x = 200
| x = |
25 | . |
| 3 |
| So, speed of the faster train = | 50 | m/sec |
| 3 |
| = |  |
50 | x | 18 |  km/hr |
| 3 | 5 |
= 60 km/hr.
Discussion:
74 comments Page 3 of 8.
Qweg said:
9 years ago
In this, we are not considering the distance that is between them? Should it be considered too?
Navin said:
9 years ago
x = 25/3
So, speed of the faster train = 50/3 m/sec.
I can't understand these steps please help me.
So, speed of the faster train = 50/3 m/sec.
I can't understand these steps please help me.
Sonam said:
8 years ago
@Adityabala.
Nice explanation. Thanks.
Nice explanation. Thanks.
Srinu said:
10 years ago
What is formula distance?
R.Rakesh KUmar said:
8 years ago
@Navin.
In question they have mentioned to calculate the speed of faster train i.e to calculate 2X
X=25/3 is the speed of the slower train and ( " If one is moving twice as fast the other" given in question).
2 * X = 2 * 25/3 => 50/3.
In question they have mentioned to calculate the speed of faster train i.e to calculate 2X
X=25/3 is the speed of the slower train and ( " If one is moving twice as fast the other" given in question).
2 * X = 2 * 25/3 => 50/3.
K.ratnababu said:
8 years ago
This is another way.
two trains opposite direction 100m+100m=200m.
200m to cover 8 seconds then,
(200m 8sec
? 3600sec
90000m that means 90k).
3600sec that mean 1 hour to cover 90000m that is 90k/h.
the train speed is 2:1.
total 3 parts.
3parts 90kilometers then,
2parts ?
60k.
two trains opposite direction 100m+100m=200m.
200m to cover 8 seconds then,
(200m 8sec
? 3600sec
90000m that means 90k).
3600sec that mean 1 hour to cover 90000m that is 90k/h.
the train speed is 2:1.
total 3 parts.
3parts 90kilometers then,
2parts ?
60k.
Garvit said:
8 years ago
Why wasn't the speed of one train 1 considered x and other considered y? Why we're both taken as x?
Eudis said:
7 years ago
From where did 18/5 come? Please explain me.
Ganesh said:
7 years ago
Consider one train x speed and another one is x one twice speed to the other train then x+2x-3x.
Reeha said:
7 years ago
@Eudis.
It's the basic conversion principle, From km/hr to m/s we can use 5/18 and the reciprocal for vice versa.
It's the basic conversion principle, From km/hr to m/s we can use 5/18 and the reciprocal for vice versa.
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