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:
254 comments Page 8 of 26.
Srikant kumar said:
1 decade ago
Best Answer could be for new person:
3600 sec me 45000 meter.
1 sec me 45000/3600 12.5 meter/sec.
30 sec me 12.5*30 = 375 meter.
Train length is 130 meter .
Bridge length will be :-375-130 = 245 meter.
3600 sec me 45000 meter.
1 sec me 45000/3600 12.5 meter/sec.
30 sec me 12.5*30 = 375 meter.
Train length is 130 meter .
Bridge length will be :-375-130 = 245 meter.
Mir said:
1 decade ago
Total distance to be covered to cross the bridge = Bridge Length+Train Length.
Speed = Distance/Time.
45*5/18 = X+130/30.
X: Length of Bridge.
130: Length of Train.
30: Time Taken to cross the bridge.
X = 245.
Speed = Distance/Time.
45*5/18 = X+130/30.
X: Length of Bridge.
130: Length of Train.
30: Time Taken to cross the bridge.
X = 245.
AVINASH said:
1 decade ago
Length of the train = 130.
Speed of the train = 45km/hr.
Time = 30sec.
Length of bridge = x+length of train.
x+length of train = Speed of the train *time.
x+130 = 45*5/18*30.
x+130 = 375.
x = 375-130.
x = 245.
Speed of the train = 45km/hr.
Time = 30sec.
Length of bridge = x+length of train.
x+length of train = Speed of the train *time.
x+130 = 45*5/18*30.
x+130 = 375.
x = 375-130.
x = 245.
Vijay said:
1 year 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.
(14)
Vaishak said:
10 years ago
I am just bewildered why they have added the train length with bridge length and why not just the bridge length because it is the actual distance the train has to pass through isn't it?Anybody please answer me.
Saikrishna said:
7 years ago
@Naveen Kumar,
That 2(130+x) = 750 come as,
2(130+x) = 750, then,
Multiply (130+x) with 2 = 260+2x = 750.
260+ 2x = 750 .
2x = 750 - 260.
2x = 490.
x= 490/2.
x= 245 meters.
You got it, this is simple way.
That 2(130+x) = 750 come as,
2(130+x) = 750, then,
Multiply (130+x) with 2 = 260+2x = 750.
260+ 2x = 750 .
2x = 750 - 260.
2x = 490.
x= 490/2.
x= 245 meters.
You got it, this is simple way.
Sidhartha said:
10 years ago
The train has to cover twice it's own length and the length of the bridge to cross the bridge so the answer provided is wrong.
It has to be 2x + 130 = 375.
Hence 2x = 245.
X = 122.50m = length of the train.
It has to be 2x + 130 = 375.
Hence 2x = 245.
X = 122.50m = length of the train.
Vichithra said:
9 years ago
@Abd.
I have solution to ur question,
Speed = 45 x (5/18) m/sec = (25/2) m/sec.
Time = 30 sec.
distance = speed x time.
=(25/2)*30.
=750/2.
Multiplication 25 with 30, is 750.
I have solution to ur question,
Speed = 45 x (5/18) m/sec = (25/2) m/sec.
Time = 30 sec.
distance = speed x time.
=(25/2)*30.
=750/2.
Multiplication 25 with 30, is 750.
A SHRUJAN said:
3 years ago
Distance travelled by Train= length of bridge + length of the train
So, x + 130m.
Speed = 45km/hr = 45 * 5/18 = 25/2 m/s.
Distance = speed * time.
25/2 * 30,
= 245m.
So, x + 130m.
Speed = 45km/hr = 45 * 5/18 = 25/2 m/s.
Distance = speed * time.
25/2 * 30,
= 245m.
(64)
Sathiyaraj said:
10 years ago
@Kavya &@Sandhya.
The entire train coaches should pass the bridge.
Here we don't know the length of the bridge, so let be x.
Train length is 130 m.
So, the distance covered by train is , 350 + x mts.
The entire train coaches should pass the bridge.
Here we don't know the length of the bridge, so let be x.
Train length is 130 m.
So, the distance covered by train is , 350 + x mts.
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