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 10 of 26.
Emme Naresh said:
10 years ago
Distance = speed/time;.
Let us bridge length = x say, train travelling distance = 130 m.
The total distance is = x + 130,
Speed = 25/2; time = 30sec.
X + 130 = (25/2) 30,
X = 375 - 130 = 245.
Let us bridge length = x say, train travelling distance = 130 m.
The total distance is = x + 130,
Speed = 25/2; time = 30sec.
X + 130 = (25/2) 30,
X = 375 - 130 = 245.
Mohan said:
1 decade ago
This problem is very easy to solve
speed(v) of train=45km/hr
length of train(d)=130m
time(t)=30sec
d=v*t
d=(45*5/18)*30
d=(25/2)*30
d=375
length of bridge(x)=d-length of train
x=375-130
x=245m
speed(v) of train=45km/hr
length of train(d)=130m
time(t)=30sec
d=v*t
d=(45*5/18)*30
d=(25/2)*30
d=375
length of bridge(x)=d-length of train
x=375-130
x=245m
Naveen kumar said:
2 decades ago
Hi jose, by cross mulyiplication method it will come as
2(130 + x) = 25*30
then 2(130 + x) = 750
then (130+x)=750/2
then (130+x)=375
then x=375-130
then finally ength of the bridge is 245m.
2(130 + x) = 25*30
then 2(130 + x) = 750
then (130+x)=750/2
then (130+x)=375
then x=375-130
then finally ength of the bridge is 245m.
Raj Kumar said:
3 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.
(11)
Rahul said:
2 decades ago
@deepika @nattu
speed= train length + bridge length
----------------------------
time taken to cross
we know train length, speed and time taken. find out bridge length.
speed= train length + bridge length
----------------------------
time taken to cross
we know train length, speed and time taken. find out bridge length.
Bhavana B Nayak said:
3 years ago
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.
= ((45*5/18)*30) - 130,
=((25/2) * 30) -130,
=(750/2) - 130,
= 375m/s - 130s,
= 245m.
(95)
Sejarc said:
7 years ago
It's simple one.
The train goes on a speed of 12.5 m/sec (45km/hr). So it crosses 375m in 30 sec.
Simply, 375 m - length of the train (130 m) =245 m (length of the bridge) => answer.
The train goes on a speed of 12.5 m/sec (45km/hr). So it crosses 375m in 30 sec.
Simply, 375 m - length of the train (130 m) =245 m (length of the bridge) => answer.
Charan singh said:
4 months ago
2 years ago.
Length of train = 130m.
Length of bridge = ?.
1hr = 3600sec.
= 3600/30.
= 120.
1km = 1000m.
= 45000/120.
= 375m.
The length of the train is less in total.
375-130 = 245.
Length of train = 130m.
Length of bridge = ?.
1hr = 3600sec.
= 3600/30.
= 120.
1km = 1000m.
= 45000/120.
= 375m.
The length of the train is less in total.
375-130 = 245.
(3)
Hashwanth said:
8 years ago
So, guys is this assumption is correct? Please tell me.
Assumption is if I thinking about a total distance, that means, does it include train's distance and the distance it traveled?
Assumption is if I thinking about a total distance, that means, does it include train's distance and the distance it traveled?
Murugan said:
1 decade ago
@Nithin.
Distance = speed x time.
So distance = 45*5/18*30.
Distance = 375 (this is the length of both train+bridge).
So we have to subtract train length (130 m).
Distance = 245.
Distance = speed x time.
So distance = 45*5/18*30.
Distance = 375 (this is the length of both train+bridge).
So we have to subtract train length (130 m).
Distance = 245.
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