Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 26)
26.
Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 5 seconds. What is the length of the fast train?
Answer: Option
Explanation:
| Relative speed = (40 - 20) km/hr = |  |
20 x | 5 |  |
m/sec = | |
50 | |
m/sec. |
| 18 | 9 |
 Length of faster train = |
|
50 | x 5 | |
m = | 250 | m = 27 | 7 | m. |
| 9 | 9 | 9 |
Discussion:
72 comments Page 6 of 8.
Nidhi said:
1 decade ago
Can anybody tell me that, then how can we calculate the length of the slower train?
J_k said:
1 decade ago
@Shweta.
If the train is travelling in same direction then we have to add both the speeds, if the train is travelling in opp. direction then we have to subtract them.
If the train is travelling in same direction then we have to add both the speeds, if the train is travelling in opp. direction then we have to subtract them.
Harpreet said:
1 decade ago
What would be the length of slower train?
Gaurav said:
1 decade ago
As the man is sitting in the train, he has the same speed as of train, so it simply means that the faster train crosses the slower train in 5 seconds.
Mj pala said:
1 decade ago
If the question is to find the length of the slower train, then?
Suman CKP said:
1 decade ago
And Suppose someone ask the speed of slower train then what will be do? Not clear?
Wangchuk said:
1 decade ago
According to formula relative speed is added when two train are moving in opposite direction and is subtracted in same direction.
Raja.k said:
1 decade ago
@Swetha.
According to this question two trains are in same starting points only but the speed of the two trains is varying. So, anyway we subtract this. Did you understand now.
According to this question two trains are in same starting points only but the speed of the two trains is varying. So, anyway we subtract this. Did you understand now.
Sindhu said:
1 decade ago
If the two trains are moving in the same direction their relative speeds are subtracted.
Shweta said:
1 decade ago
Can anyone tell me when we have to add relative speed and when we have to subtract?
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