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:
200 m
225 m
245 m
250 m
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 25 of 25.

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.
(24)

Kuenzang wangmo said:   6 months ago
How 5/18 came? Please explain to me.
(15)

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.
(9)

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.
(40)

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.
(22)


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