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 6 of 11.
Ram said:
1 decade ago
They are starting at two different points and moving in opposite direction. They are not starting at the same point.
Ragi said:
1 decade ago
For what purpose we are converting the kilometer into meter? can't we solve this problem with length 2km.
Bismillah khan said:
1 decade ago
No need to convert Km to m, conversion is due to hr to sec because answer is in sec.
Aasif Khan said:
1 decade ago
This is due, when we calculate time= distance/speed,
Speed is 125/3 m/sec. Therefore when we divide 2000m with 125/3 it becomes 2000 multiply by 3/125.
Speed is 125/3 m/sec. Therefore when we divide 2000m with 125/3 it becomes 2000 multiply by 3/125.
Divyan said:
1 decade ago
Why we are not simplifying 125/3? Please help me guys.
Avinash Upadhyay said:
1 decade ago
@Divyan, here we are converting the speed into meter/sec from km/hr .
(1km = 1000m
1hr = 3600sec
m/sec = 1000/3600 = 5/18.)
150*25/3 = 125/3.
And relative speed comes into picture when two given objects in the questions are in motion.
(1km = 1000m
1hr = 3600sec
m/sec = 1000/3600 = 5/18.)
150*25/3 = 125/3.
And relative speed comes into picture when two given objects in the questions are in motion.
Ajit vishwakarma said:
1 decade ago
What do you mine time taken by the slower train to cross the faster train?
ParthShah said:
1 decade ago
Point 1: Trains are running in opposite directions so the slower train will cross the faster one.
Point 2: The time taken by slower train to cross faster train would be equal to the vice versa.
Point 2: The time taken by slower train to cross faster train would be equal to the vice versa.
Anand said:
1 decade ago
Why 5/18?
Amrutha said:
1 decade ago
In the above given that:
T = x+y/u+v for opposite direction.
Can you please apply in this problem?
T = x+y/u+v for opposite direction.
Can you please apply in this problem?
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