Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 8)
8.
A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Answer: Option
Explanation:
| Formula for converting from km/hr to m/s: X km/hr = |  |
X x | 5 |  |
m/s. |
| 18 |
| Therefore, Speed = | |
45 x | 5 | m/sec |
= | 25 | m/sec. |
| 18 | 2 |
Total distance to be covered = (360 + 140) m = 500 m.
| Formula for finding Time = | |
Distance | |
| Speed |
 Required time = |
|
500 x 2 | sec |
= 40 sec. |
| 25 |
Discussion:
78 comments Page 7 of 8.
ANIL said:
7 years ago
Given,
length of the train =360m,
speed of train =45km/h,
length of the bridge =140m,
time =T.
Now convert 45km/h=45*5/18=225/18m/s.
Total length=360m+140m=500m.
We know speed =distance/time.
=> 225/18=500/T.
=> T=500*18/225.
=> T=40s.
length of the train =360m,
speed of train =45km/h,
length of the bridge =140m,
time =T.
Now convert 45km/h=45*5/18=225/18m/s.
Total length=360m+140m=500m.
We know speed =distance/time.
=> 225/18=500/T.
=> T=500*18/225.
=> T=40s.
Gurwinder singh said:
7 years ago
Why (x*5/18) mps?
Prasad kapal said:
7 years ago
But we added 500 with 140.
Anush said:
6 years ago
Why we are adding the train length with bridge length?
(1)
Sai said:
6 years ago
450mts ----> 36sec.
500mts ---> 40sec.
500mts ---> 40sec.
(1)
Rohan said:
6 years ago
Why we have to add the length of the train?
Nibha said:
6 years ago
Why 140m is added?
(1)
Shubham Jain said:
6 years ago
How come 25/2?
(1)
Madhav Kulkarni said:
6 years ago
Train Length=360 Speed=45km/h=45*(5/18)=12.15m/s.
So Train Speed is 12.15m/s.
Bridge Length = 140.
Speed = Distance/Time.
12.15 = 360+140/time.
Time = 360+140/12.15.
= 500/12.5.
= 40.
So, the Time Require to cross 140m Bridge is 40sec.
So Train Speed is 12.15m/s.
Bridge Length = 140.
Speed = Distance/Time.
12.15 = 360+140/time.
Time = 360+140/12.15.
= 500/12.5.
= 40.
So, the Time Require to cross 140m Bridge is 40sec.
(5)
Dheeraj said:
5 years ago
Here length of train =360m.
Length of bridge =140m.
Speed of train =45km/h.
To convert into m/s multiplying it with 5/18.
Now to find time=Distance/speed.
Distance=length of both train and bridge.
Distance=140+360.
Speed=45*5/18=25/2.
Time=500/25/2=500*2/25=40.
Length of bridge =140m.
Speed of train =45km/h.
To convert into m/s multiplying it with 5/18.
Now to find time=Distance/speed.
Distance=length of both train and bridge.
Distance=140+360.
Speed=45*5/18=25/2.
Time=500/25/2=500*2/25=40.
(7)
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