Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 14)
14.
Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is:
Answer: Option
Explanation:
| Relative speed = (60 + 40) km/hr = |  |
100 x | 5 |  m/sec |
= | |
250 | m/sec. |
| 18 | 9 |
Distance covered in crossing each other = (140 + 160) m = 300 m.
| Required time = | |
300 x | 9 | sec |
= | 54 | sec = 10.8 sec. |
| 250 | 5 |
Discussion:
42 comments Page 5 of 5.
Priyavel said:
1 decade ago
Hello friend
1)speed=distance/time
2)here time should be calculate so time=distance/ speed
3) distance=300 (opposite direction so we add it)
4)time= 100 (opposite direction so we add it) then we want to convert km into m,hour into sec so we multiply 5/18 so we get it 100*5/18=250/9
5)time=300(distance)/(250/9)=300*9/250.
i think u get clear id
1)speed=distance/time
2)here time should be calculate so time=distance/ speed
3) distance=300 (opposite direction so we add it)
4)time= 100 (opposite direction so we add it) then we want to convert km into m,hour into sec so we multiply 5/18 so we get it 100*5/18=250/9
5)time=300(distance)/(250/9)=300*9/250.
i think u get clear id
Nisha said:
1 decade ago
Why 9/250?
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