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:
245 comments Page 5 of 25.
Mahesh said:
6 years ago
In order to convert a Km/hr to m/sec.
For 1km/hr.
1km=1000m.
1hr=3600sec.
Now 1000/3600=0.277m/sec.
for 45 km/hr.
45km= 45000.
1hr= 3600.
Now 45000/3600=12.5m/sec.
time taken is equal to 30 sec.
Let the length of the bridge be x meters.
Then 130+x/30= 12.5.
= 130+x = 12.5 * 30.
= x = 12.5 * 30-130.
Now x = 245m.
For 1km/hr.
1km=1000m.
1hr=3600sec.
Now 1000/3600=0.277m/sec.
for 45 km/hr.
45km= 45000.
1hr= 3600.
Now 45000/3600=12.5m/sec.
time taken is equal to 30 sec.
Let the length of the bridge be x meters.
Then 130+x/30= 12.5.
= 130+x = 12.5 * 30.
= x = 12.5 * 30-130.
Now x = 245m.
Ahmad said:
7 years ago
(130 + x)/30 = 25/2.
What is meant by this?
What is meant by this?
(1)
Abhi singh said:
7 years ago
So,
45 * 5/18 = 25/2 = 12.5.
Speed = 12.5,
Distance = time * speed = 30 * 12.5 = 375.
130+x = 375,
x = 375-130,
x = 245m/s.
45 * 5/18 = 25/2 = 12.5.
Speed = 12.5,
Distance = time * speed = 30 * 12.5 = 375.
130+x = 375,
x = 375-130,
x = 245m/s.
Banda said:
7 years ago
Hi, Good explanation. Thanks all.
(1)
ARYAN said:
7 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)
Hashwanth said:
7 years ago
So, guys is this assumption is correct? Please tell me.
Assumption is if I thinking about a total distance, that means, does it include train's distance and the distance it traveled?
Assumption is if I thinking about a total distance, that means, does it include train's distance and the distance it traveled?
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.
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