Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 9)
9.
Two trains are moving in opposite directions @ 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is:
Answer: Option
Explanation:
Relative speed = (60+ 90) km/hr
| = |  |
150 x | 5 |  m/sec |
| 18 |
| = | |
125 | m/sec. |
| 3 |
Distance covered = (1.10 + 0.9) km = 2 km = 2000 m.
| Required time = | |
2000 x | 3 | sec = 48 sec. |
| 125 |
Discussion:
107 comments Page 9 of 11.
Ramya said:
1 decade ago
How 5/18 came? Can you please explain me?
Santhu said:
10 years ago
Km/hr convert meter/sec=5/18 multiple.
Jyothi said:
10 years ago
km/hr = 1000 m/3600 sec = 5/18 m/sec [1000/3600 = 5/18].
Geenee said:
10 years ago
Why km is converted into meter though there all information is in kilometer?
Krishan said:
10 years ago
Why it is explicitly mentioned "time taken for faster train to cross slower train"?
I think time taken will be same for both the trains.
I think time taken will be same for both the trains.
Adm said:
10 years ago
But here don't we need to consider length of longer train only because faster will cross beforehand.
Karthik said:
9 years ago
How to get 125/3?
Amrutha devi said:
9 years ago
Hi, @Karthik.
The relative speed between two trains is =90 Km/hr--> equation1.
But 1 Km=1000 m; and 1 hr=3600 sec.
Now these two values are substituted in equation1 because we want to convert Km/hr into m/sec because the answer was in m/sec. =(90*1000)/3600 or 90*(1000/36000).
Simplify above like in thousand two zeros are cancelled by denominator value of two zeros(3600), then we get 90*(10/36).
Then again simplify the equation by using 2 table cancel the 10 and 36, then we get 90*(5/18), then it is again simplified using 6 table cancel the 18 and 90, then we get 25*(5/3).
so, this is again simplified, and got 125/3.
The relative speed between two trains is =90 Km/hr--> equation1.
But 1 Km=1000 m; and 1 hr=3600 sec.
Now these two values are substituted in equation1 because we want to convert Km/hr into m/sec because the answer was in m/sec. =(90*1000)/3600 or 90*(1000/36000).
Simplify above like in thousand two zeros are cancelled by denominator value of two zeros(3600), then we get 90*(10/36).
Then again simplify the equation by using 2 table cancel the 10 and 36, then we get 90*(5/18), then it is again simplified using 6 table cancel the 18 and 90, then we get 25*(5/3).
so, this is again simplified, and got 125/3.
Murali said:
9 years ago
T = D/S.
T = 2km/150km/hr.
Is this is right?
Please, Tell me how to solve.
T = 2km/150km/hr.
Is this is right?
Please, Tell me how to solve.
B.K.S said:
9 years ago
Length should always be added irrespective of direction and both trains are passing each other in same time interval.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers