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 3 of 25.
Vaghela Milankumar said:
3 years ago
4.5x 5/18 = 12.5
12.5 x 30 = 375
375 - 130 = 245 ans.
12.5 x 30 = 375
375 - 130 = 245 ans.
(55)
Prakash said:
3 years ago
Why are you people adding the bridge distance?
If in case the bridge distance is lesser than the train distance, then how it will be calculated?
If in case the bridge distance is lesser than the train distance, then how it will be calculated?
(19)
Adaeze Thompson said:
3 years ago
How do you get 25/2? Explain, please.
(15)
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)
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)
Deepak Sahoo said:
4 years ago
Thanks for explaining the answer @Fathima.
(1)
Sid said:
4 years ago
Why it is +x, it also be -x, right?
(1)
Sonik Salam said:
4 years ago
260+2x=750.
2x=750-260,
2x=490,
And x = 490/2 = 245m.
2x=750-260,
2x=490,
And x = 490/2 = 245m.
(1)
Arup Kumar subudhi said:
4 years ago
Train Speed is 45 km/sec = (45*5)/18 = 25/2 m/s.
= (25*15)/(2*15) m/s,
= 375/30 m/s.
375 m in 30 sec, so bridge length is = 375 - 130 = 245m.
= (25*15)/(2*15) m/s,
= 375/30 m/s.
375 m in 30 sec, so bridge length is = 375 - 130 = 245m.
(2)
Sanilam Guha said:
4 years ago
(0.130+x) = (45 * 30)/3600.
If assume x is bridge length;
OR, 0.130 + x = 0.375.
OR, X = 0.375 - 0.130.
OR, X = 0.245 KM OR 245 M.
Am I right?
If assume x is bridge length;
OR, 0.130 + x = 0.375.
OR, X = 0.375 - 0.130.
OR, X = 0.245 KM OR 245 M.
Am I right?
(2)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers