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:
249 comments Page 3 of 25.
WDL said:
3 years ago
Speed = 45*(5/18)=25/2 m/s.
Displacement = speed * time(here time is 30sec).
X + 130 = 25/2 * 30.
2(X + 130) =750.
2X + 260 = 750.
X = (750-260)/2= 245m.
Displacement = speed * time(here time is 30sec).
X + 130 = 25/2 * 30.
2(X + 130) =750.
2X + 260 = 750.
X = (750-260)/2= 245m.
(12)
Lokesh said:
2 years ago
45km In 1 hr.
45km In 60 min.
45 km In 60*60 seconds
45000m In 60*60 seconds
45000/120 In 30 seconds
375.m in 30 seconds.
375m including with train length so the train length is;
375 - 130 = 245 m ANS.
45km In 60 min.
45 km In 60*60 seconds
45000m In 60*60 seconds
45000/120 In 30 seconds
375.m in 30 seconds.
375m including with train length so the train length is;
375 - 130 = 245 m ANS.
(12)
Vijay said:
8 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.
(11)
Raj Kumar said:
2 years ago
My Question is why we should convert 45 km/hr into meters/per second which is a unit of speed instead of that we can convert 130/30 which is also equal to speed?
Anyone, explain this to me.
Anyone, explain this to me.
(10)
Akash S said:
2 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.
(10)
Prakash said:
3 years ago
We have to calculate speed.
Speed = 45*5/18=25/2 m/s.
Time is given t= 30 sec.
Let's find the length of the bridge,
Let the length of the bridge is X.
And whenever a train crosses the bridge then the total distance covered by the train is the length of the bridge it's own length (train's length).
According to the motion's 1st law distance or displacement = speed * time.
X + 130 = 25/2 * 30.
2(X + 130) =750.
2X + 260 = 750.
X = (750-260)/2= 245m.
Speed = 45*5/18=25/2 m/s.
Time is given t= 30 sec.
Let's find the length of the bridge,
Let the length of the bridge is X.
And whenever a train crosses the bridge then the total distance covered by the train is the length of the bridge it's own length (train's length).
According to the motion's 1st law distance or displacement = speed * time.
X + 130 = 25/2 * 30.
2(X + 130) =750.
2X + 260 = 750.
X = (750-260)/2= 245m.
(9)
Sidheswar Pradhan said:
3 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.
(6)
Anonymous said:
3 months ago
I am not getting this answer. Anyone, please help me by explaining it.
(5)
Shabeer said:
2 months ago
How 5/18 will came? Please explain.
(4)
Kavya said:
6 years ago
D= S * T.
D = 45 * 5/18 * 30 = 375m,
375-130=245m.
D = 45 * 5/18 * 30 = 375m,
375-130=245m.
(2)
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