Aptitude - Problems on Trains - Discussion

Length of bridge = (speed of the train * time taken to cross the bridge) - length of the train.
= ((45*5/18)*30) - 130,
=((25/2) * 30) -130,
=(750/2) - 130,
= 375m/s - 130s,
= 245m.

Length of train 130, speed 45 km/hr it crosses the bridge in 30 seconds.
What is the length of the bridge?
45km = 45000 m
1hr = 3600 s.

So
45000/3600 = 12.5 m/s
the train crosses a bridge in 30 sec then
12.5 * 30 = 375
The train travelled 375 in 30 sec.
Then distance - train length = bridge length.
375 - 130 =245.
bridge length = 245.

Convert speed from km/hr to m/sec(km/hr=5/18 m/s).
Then,as we know DISTANCE=SPEED *TIME.
D = [45 * (5/18)] * 30 sec.

Then, D = 375m(This is the total distance)
So, we can subtract the total distance from the length of the train),
The length of the train is = 375 - 130 = 245m.

Solution:

45 * 5/18 = 12.5,
12.5 * 30 = 375,
375 - 130 = 245,
So, this is how we get 245.

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.

To find the length of the bridge, we need to calculate the distance the train travels in 30 seconds.

First, we convert the train's speed from km/hr to m/s:

Speed in m/s = (Speed in km/hr * 1000)/3600
So, the train's speed in m/s = (45 km/hr * 1000)/3600 = 12.5 m/s.

Now we can calculate the distance the train travels in 30 seconds:
Distance = Speed * Time.

Distance = 12.5 m/s * 30 s = 375 meters.

Since the train is 130 meters long, the remaining distance must be the length of the bridge:
Length of the bridge = Distance - Length of the train.

Length of the bridge = 375 m - 130 m = 245 meters.

Therefore, the length of the bridge is 245 meters.

4.5x 5/18 = 12.5
12.5 x 30 = 375
375 - 130 = 245 ans.

Length of train = 130m
Length of bridge = ?
1hr = 3600sec
= 3600/30
= 120.

1km = 1000m
= 45000/120
= 375m
The length of the train is less total.
375-130 = 245.

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.

Given TD = 130m, speed = 45km/h, Time = 30sec.
And Length of the Station = x.

speed = 45*5/18 .
=225/18.
So, the speed =25/2.

know the length of the station,
x + TD = speed * Time
x + 130 = 25/2 * 30
x + 130 = 12.5 * 30
x + 130 = 375.
x = 375 - 130,
Final x = 245.
The correct answer is option C.