Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 3)
3.
The length of the bridge, which a train 130 metres long and travelling at 45 km/hr can cross in 30 seconds, is:
Answer: Option
Explanation:
| Speed = |  |
45 x | 5 |  m/sec |
= | |
25 | m/sec. |
| 18 | 2 |
Time = 30 sec.
Let the length of bridge be x metres.
| Then, | 130 + x | = | 25 |
| 30 | 2 |
2(130 + x) = 750
x = 245 m.
Video Explanation: https://youtu.be/M_d8WufJWKc
Discussion:
254 comments Page 14 of 26.
ARYAN said:
8 years ago
Length of the train = 130m.
speed =45km/h so, 45/3.6=12.5.
12.5*time=12.5*30=375m.
length of the bridge = [375-130] = 245m ANS.
speed =45km/h so, 45/3.6=12.5.
12.5*time=12.5*30=375m.
length of the bridge = [375-130] = 245m ANS.
(1)
Amit said:
10 years ago
Here, v = 45 km/hr = 45 * (1000/3600) = 25/2 m/s.
T = 30s.
S = vt = (25/2) * 30 = 375 m.
Now, L = 375 - 130 = 245 m (Ans).
T = 30s.
S = vt = (25/2) * 30 = 375 m.
Now, L = 375 - 130 = 245 m (Ans).
Dumpati Mahesh said:
1 decade ago
Here we should consider as per the problem that, Train is passing only one time through the bridge. So 130+B.L. Only sanjay.
Nattu said:
2 decades ago
But crossing chould mean the whole train should be off the bridge right? So why should we subtract the length of the train?
Sasidhar nrit said:
8 years ago
45 km/hr.
45000/60min = 750m /min.
travelling 750m per minute,
750m/30sec = 375m,
than 375m-130m = 245m.
Is this correct?
45000/60min = 750m /min.
travelling 750m per minute,
750m/30sec = 375m,
than 375m-130m = 245m.
Is this correct?
Malini said:
1 decade ago
We know that,
Speed=45 km/hr.
=45*5/18=25/2 m/sec.
Length=speed*time.
130+x=25/2*30.
130+x=375.
x=375-130.
x=245.
Speed=45 km/hr.
=45*5/18=25/2 m/sec.
Length=speed*time.
130+x=25/2*30.
130+x=375.
x=375-130.
x=245.
Harichandan Sabat said:
8 years ago
1 km --- 1000 metre & 1 hour --- 3600sec whenever you divide 1km/1 hour then 1000 metre/3600 sec equals to 5/18 m/s.
Sanjay said:
1 decade ago
B.L. = Bridge Length.
For crossing the bridge distance should be 130+ (B.L) +130.
Then why you are taking 130 + B.L?
For crossing the bridge distance should be 130+ (B.L) +130.
Then why you are taking 130 + B.L?
Pobitro Ghosh said:
9 years ago
Hi,
I solved it differently.
Like,
Total speed= 45*5/18=25/2*30=375,
Actual speed of the train= 375-130=245.
Ans: 245.
I solved it differently.
Like,
Total speed= 45*5/18=25/2*30=375,
Actual speed of the train= 375-130=245.
Ans: 245.
Nusrat Fathima said:
2 decades ago
Thanks karthik
Sai the method mentioned by u is also a right method to solve the above problem..... Good thinking.
Sai the method mentioned by u is also a right method to solve the above problem..... Good thinking.
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