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 2 of 8.
Shital said:
6 years ago
Please, explain this how 250/9 to 27 * 7/9?
(3)
Rohit Parmar said:
6 years ago
How to simplify 250/9 to 27*7/9?
Please explain clearly.
Please explain clearly.
M.vishwa Mohawk reddy said:
6 years ago
How came 27 7/9? I am not getting, Please explain.
Tatikonda Dinesh said:
6 years ago
How to came 27 7/9?
Anybody, Please explain.
Anybody, Please explain.
Sumukh said:
6 years ago
Since the faster train is passing man sitting inside the slower train in 5 seconds. The length of slower train may be treated as man distance which is negligible just like pole. So, the right answer is C.
Shashi said:
7 years ago
Rather than crossing man, if they asked the length of the slower train, then what will be the method?
Beeresh said:
7 years ago
Simple method.
Speed =distance/time.
Relative speed (if same direction)=s1-s2.
Consider usefull formula s1-s2=(l1+l2)/time.
Here l1= trian 1 length= x meters.
L2= 0 meters ( person who is sitting in train),
Time taken to cross person is t=5 sec,
40-20 km/h = x/5,
20km/h =x/5,
20*5/18 =x/5,
(50/9)*5 =x,
250/9=x,
27.77 => answer.
Speed =distance/time.
Relative speed (if same direction)=s1-s2.
Consider usefull formula s1-s2=(l1+l2)/time.
Here l1= trian 1 length= x meters.
L2= 0 meters ( person who is sitting in train),
Time taken to cross person is t=5 sec,
40-20 km/h = x/5,
20km/h =x/5,
20*5/18 =x/5,
(50/9)*5 =x,
250/9=x,
27.77 => answer.
(1)
Kanishk jain said:
7 years ago
Actually, it means that the length of the faster train relative to the slower train.
That's why the answer is 250/9.
That's why the answer is 250/9.
Madhusudhan said:
7 years ago
How to simplify 250/9 to 27*7/9? Please explain clearly.
Pratik Patil said:
7 years ago
Just consider that man is running at speed of 20 km/hr, then find the relative speed between train and man i.e. (40-20)km/hr=20km/hr=20*5/18 m/s=50/9 m/s.
The length of train (faster) = speed X time = 5*50/9 = 27 7/9 m.
The length of train (faster) = speed X time = 5*50/9 = 27 7/9 m.
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