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:
250 comments Page 1 of 25.
Draco said:
1 month ago
So the train must go faster than the man to pass him.
S = D/T.
Meters to km = 18/5,
s = d/t,
d = 125 x 18/5 = 450.
t = 10.
s = 450/10 = 45.
The speed we calculate (45 km/hr) is the extra speed the train has compared to the man.
45 + 5 = 50km/hr.
S = D/T.
Meters to km = 18/5,
s = d/t,
d = 125 x 18/5 = 450.
t = 10.
s = 450/10 = 45.
The speed we calculate (45 km/hr) is the extra speed the train has compared to the man.
45 + 5 = 50km/hr.
(1)
Akash S said:
5 months ago
A= 130m.
Speed of train = 45km/hr in 30 seconds.
45 = 30 * 5/18.
X = 150/18 * 45 m/s.
X = 375m/s.
Length = X - A.
375-130 = 245.
Speed of train = 45km/hr in 30 seconds.
45 = 30 * 5/18.
X = 150/18 * 45 m/s.
X = 375m/s.
Length = X - A.
375-130 = 245.
(21)
Shabeer said:
5 months ago
How 5/18 will came? Please explain.
(12)
Sidheswar Pradhan said:
6 months ago
1 km/hr = 1km/1hr.
= 1000 m/3600 sec,
= 10/36 m/s,
= 5/18 m/s.
= 1000 m/3600 sec,
= 10/36 m/s,
= 5/18 m/s.
(12)
Anonymous said:
6 months ago
I am not getting this answer. Anyone, please help me by explaining it.
(7)
Vikash Kumar Bharti 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.
(37)
Fearless said:
10 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.
(59)
Vijay said:
11 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.
(13)
Kuenzang wangmo said:
12 months ago
How 5/18 came? Please explain to me.
(19)
Jimian said:
1 year 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.
(27)
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