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 1 of 25.
Vikash Kumar Bharti said:
3 months ago
Given, train length s = 130.
Let, the bridge length is x.
Total passing length = velocity * time.
S + x = vt.
130 + x = 45 * (5/18) * 30.
x = 245m.
Let, the bridge length is x.
Total passing length = velocity * time.
S + x = vt.
130 + x = 45 * (5/18) * 30.
x = 245m.
(22)
Fearless said:
4 months ago
The speed of train in sec = 45000/3600 = 12.5sec.
distance travel by train in 30 sec = 12.5 * 30 = 375m,
lenght of train = 130m.
Length of bridge = distance traveled by the train - length of train.
= 375-130 = 245m.
distance travel by train in 30 sec = 12.5 * 30 = 375m,
lenght of train = 130m.
Length of bridge = distance traveled by the train - length of train.
= 375-130 = 245m.
(39)
Vijay said:
5 months ago
1 km = 1000 m,
1 hr has 3600 sec.
So, 1 km/hr = 1000m/3600s = 5/18 m/s.
To convert the speed from km/hr to m/s, multiply the speed by 5/18.
To convert the speed from m/s to km/hr, multiply the speed by 18/5.
1 hr has 3600 sec.
So, 1 km/hr = 1000m/3600s = 5/18 m/s.
To convert the speed from km/hr to m/s, multiply the speed by 5/18.
To convert the speed from m/s to km/hr, multiply the speed by 18/5.
(9)
Kuenzang wangmo said:
6 months ago
How 5/18 came? Please explain to me.
(15)
Jimian said:
9 months ago
Given, train length s = 130.
Let, the bridge length is x.
Total passing length = velocity * time.
S + x = vt.
130 + x = 45 * (5/18) * 30.
x = 245m.
Let, the bridge length is x.
Total passing length = velocity * time.
S + x = vt.
130 + x = 45 * (5/18) * 30.
x = 245m.
(24)
Muzammil said:
1 year ago
Length of train 130, speed 45 km/hr it crosses the bridge in 30 seconds.
What is the length of the bridge?
45km = 45000 m
1hr = 3600 s.
So
45000/3600 = 12.5 m/s
the train crosses a bridge in 30 sec then
12.5 * 30 = 375
The train travelled 375 in 30 sec.
Then distance - train length = bridge length.
375 - 130 =245.
bridge length = 245.
What is the length of the bridge?
45km = 45000 m
1hr = 3600 s.
So
45000/3600 = 12.5 m/s
the train crosses a bridge in 30 sec then
12.5 * 30 = 375
The train travelled 375 in 30 sec.
Then distance - train length = bridge length.
375 - 130 =245.
bridge length = 245.
(93)
Yuvashree R said:
1 year ago
Convert speed from km/hr to m/sec(km/hr=5/18 m/s).
Then,as we know DISTANCE=SPEED *TIME.
D = [45 * (5/18)] * 30 sec.
Then, D = 375m(This is the total distance)
So, we can subtract the total distance from the length of the train),
The length of the train is = 375 - 130 = 245m.
Then,as we know DISTANCE=SPEED *TIME.
D = [45 * (5/18)] * 30 sec.
Then, D = 375m(This is the total distance)
So, we can subtract the total distance from the length of the train),
The length of the train is = 375 - 130 = 245m.
(84)
Shamama Mubarak said:
1 year ago
Length of train = 130m
Length of bridge = ?
1hr = 3600sec
= 3600/30
= 120.
1km = 1000m
= 45000/120
= 375m
The length of the train is less total.
375-130 = 245.
Length of bridge = ?
1hr = 3600sec
= 3600/30
= 120.
1km = 1000m
= 45000/120
= 375m
The length of the train is less total.
375-130 = 245.
(54)
Adesh Katiya said:
2 years ago
l = ?
Train length =130m
Speed = 45km/hr
Time = 30s.
30s = time(130+l(m)).
30s = (130+l)m/45km/hr.
30s = (130+l)m/45 * 5/18m/s.
30s = 130+l/(25/2)m/s.
30s = (130+l) * 2/25.
30 * 25 = (130 +l)* 2.
15*25 = 130 + l.
375 - 130 = l.
245m = l.
Train length =130m
Speed = 45km/hr
Time = 30s.
30s = time(130+l(m)).
30s = (130+l)m/45km/hr.
30s = (130+l)m/45 * 5/18m/s.
30s = 130+l/(25/2)m/s.
30s = (130+l) * 2/25.
30 * 25 = (130 +l)* 2.
15*25 = 130 + l.
375 - 130 = l.
245m = l.
(13)
Kiranmaye said:
2 years ago
@Rajesh.
We take 5/18 to convert from km/h into m/s.
We take 5/18 to convert from km/h into m/s.
(23)
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