Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 7)
7.
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:
Answer: Option
Explanation:
Let the length of each train be x metres.
Then, distance covered = 2x metres.
Relative speed = (46 - 36) km/hr
| = |  |
10 x | 5 |  m/sec |
| 18 |
| = | |
25 | m/sec |
| 9 |
 |
2x | = | 25 |
| 36 | 9 |
2x = 100
x = 50.
Discussion:
232 comments Page 20 of 24.
Rajkumar said:
1 decade ago
Equal length, L1=L2
speed s1,s2
in same direction formula, time=(L1+L2)/(s1-s2) m/sec.
s1=46 km/hr
s2=36 km/hr
time=36 sec
time=(L1+L2)/(46-36)*5/18
36=(L1+L1)/(10)*5/18 [:.Equal length, L1=L2]
36=2L/(50/18)
36=(2L*18)/50
2L=(36*50)/18
2L=100
L=50 m
Using this formula.
speed s1,s2
in same direction formula, time=(L1+L2)/(s1-s2) m/sec.
s1=46 km/hr
s2=36 km/hr
time=36 sec
time=(L1+L2)/(46-36)*5/18
36=(L1+L1)/(10)*5/18 [:.Equal length, L1=L2]
36=2L/(50/18)
36=(2L*18)/50
2L=(36*50)/18
2L=100
L=50 m
Using this formula.
Arup said:
1 decade ago
Why we have to subtract (46-36)kmph?
though it is relative speed and both of them are coming to each other it should get added i.e (46+36)
though it is relative speed and both of them are coming to each other it should get added i.e (46+36)
Hasi said:
1 decade ago
Distance traveled by train =x
2 trains have same length
there are two trains traveled at the same time
means total distance traveled by the train =2x
Relative distance of the train is =(46-36)=10km/hr
but options are given in sec so,we have to convert into m/sec
10*(5/18)=25/9
total distance=speed*time
2x=(25/9)*36
2x=100
x=50
2 trains have same length
there are two trains traveled at the same time
means total distance traveled by the train =2x
Relative distance of the train is =(46-36)=10km/hr
but options are given in sec so,we have to convert into m/sec
10*(5/18)=25/9
total distance=speed*time
2x=(25/9)*36
2x=100
x=50
Vinayak said:
1 decade ago
Can we calculate this example by (a+b) / (u-v)?
Ster said:
1 decade ago
2x as distance only makes sense if the faster train start behind the slower train. If they were right next to each other at the start, the distance traveled would only be x. Question does not clarify this. Please amend.
Venkatesh said:
1 decade ago
Hi jelli, can you give a important equations used in that kind of problems.
Venkatesh said:
1 decade ago
Thanks jelli.
Sid said:
1 decade ago
What is relative speed. Please explain me in somewhat detail manner. Cant understand.
Pavithra said:
1 decade ago
Why not we take 2x/46 ?
Rammurthy said:
1 decade ago
How this equation: 2x/36 = 25/9?
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