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:
247 comments Page 14 of 25.
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:
7 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:
8 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.
SK Lodhi said:
1 decade ago
130+B = 30 Sec.*45*5/18 m/s(time*speed).
130+B = 375 m.
Where B = length of the Bridge = 375 - 130 = 245 meters.
130+B = 375 m.
Where B = length of the Bridge = 375 - 130 = 245 meters.
Prakash said:
1 decade ago
speed=[45*(5/18)]=25/2 m/hr
time=30 sec
s=d/t
distance= speed*time
(25/2)* 30=375
375-130= 245
is this ryt
time=30 sec
s=d/t
distance= speed*time
(25/2)* 30=375
375-130= 245
is this ryt
Sohini nandi said:
1 decade ago
Train goes in 30 sec : 30*45*(5/18) = 375 m.
Its length = 130 m.
Therefore bridges length = (375-130)m = 245 m.
Its length = 130 m.
Therefore bridges length = (375-130)m = 245 m.
Sunil Kumar said:
1 decade ago
Let bridge length x m then.
Length of train = 130.
Speed 45*5/18 = 12.5.
Distance=12.5*30 = 375.0-130 = 245.
Length of train = 130.
Speed 45*5/18 = 12.5.
Distance=12.5*30 = 375.0-130 = 245.
Anil Bhadani said:
8 years ago
45 km *30 sec /3600 sec = 375m.
So length of bridge = passes length - length of train = 375m - 130 m = 245m.
So length of bridge = passes length - length of train = 375m - 130 m = 245m.
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