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:
250 comments Page 8 of 25.
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:
11 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.
(13)
Vaishak said:
9 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:
8 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:
9 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.
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)
Ananth G said:
1 decade ago
@Rohit,
Length=(speed*time).
What you know take left side others stay right side, listen down.
Length
------- = speed {(130+X)/30=25/2,
Time
Than you workout cross multiply method then you get 245m.
Length=(speed*time).
What you know take left side others stay right side, listen down.
Length
------- = speed {(130+X)/30=25/2,
Time
Than you workout cross multiply method then you get 245m.
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