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:
249 comments Page 6 of 25.
Sasidhar nrit said:
7 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?
Ishwarya said:
7 years ago
Shouldn't we are considering from the time the train's front enters the bridge till the tail is completely off the bridge as 30 seconds?
Then it would be 375- (130+130) =115m.
Then it would be 375- (130+130) =115m.
Leki said:
7 years ago
Distance= Time * speed.
1km=1000m.
1hr=3600sec.
Time=d/t.
=1000/3600=5/18.
There distance: 5/18*45=25/2.
Length=t/d*s.
130+x=25/2*30.
130+x=375.
X = 375-130 = 245.
1km=1000m.
1hr=3600sec.
Time=d/t.
=1000/3600=5/18.
There distance: 5/18*45=25/2.
Length=t/d*s.
130+x=25/2*30.
130+x=375.
X = 375-130 = 245.
Vijaybalajimuthujayam said:
7 years ago
Good explanation, Thanks @Nursat Fathima.
Agnel said:
7 years ago
45*5/18 = 12.5,
12.5*30 = 375,
375-130 = 245.
12.5*30 = 375,
375-130 = 245.
Ani said:
7 years ago
@Sarang you are correct this is the easiest way to solve this problem.
As
Distance= time * speed.
D=45*5/18=25/2(speed)*30(time),
Actual distance=25 * 15=375.
Then bridge distance=Actual distance (375)- train Distance (130)=245.
As
Distance= time * speed.
D=45*5/18=25/2(speed)*30(time),
Actual distance=25 * 15=375.
Then bridge distance=Actual distance (375)- train Distance (130)=245.
Sarang said:
8 years ago
Distance = speed*time,
D= 45* 5/18*30,
D= 5*5/2* 30,
D= 5 * 5 * 15 = 375,
D= 375- 130= 245.
D= 45* 5/18*30,
D= 5*5/2* 30,
D= 5 * 5 * 15 = 375,
D= 375- 130= 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.
Ravi said:
8 years ago
How do you take 5/18?
Kuma said:
8 years ago
Speed=Distance/Time.
45*5/18=Distance/30,
375= Distance,
Length= 375-130=245.
45*5/18=Distance/30,
375= Distance,
Length= 375-130=245.
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