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:
252 comments Page 16 of 26.
Karthick said:
1 decade ago
Formula is = (Length of the train + Length of the object)=(Speed of the train* Time of the object).
Sundaram said:
2 decades ago
Because train cross the bridge so we must add the length then only we will get the bridge length.
Madhu said:
1 decade ago
We should convert km/hr to m/sec, so we should multiply the 45km/hr by 5/18,then we get 25m/sec.
Suren said:
1 decade ago
@Sai.
Your method is fantastic and very easy to understand. Great job! keep it up man. Thanks!
Your method is fantastic and very easy to understand. Great job! keep it up man. Thanks!
Sumit said:
9 years ago
@Guru.
5/18 is here because to converting distance km/h to m/s it's a formula to convert.
5/18 is here because to converting distance km/h to m/s it's a formula to convert.
Sarang said:
8 years ago
Distance = speed*time,
D= 45* 5/18*30,
D= 5*5/2* 30,
D= 5 * 5 * 15 = 375,
D= 375- 130= 245.
D= 45* 5/18*30,
D= 5*5/2* 30,
D= 5 * 5 * 15 = 375,
D= 375- 130= 245.
Sunny said:
2 decades ago
Hey boopathi its simple.
2(130+x)=750
130+x=750/2
130+x=375
x=375-130
Therefore x = 245.
2(130+x)=750
130+x=750/2
130+x=375
x=375-130
Therefore x = 245.
BLESINA DASARI said:
3 years ago
Solution:
45 * 5/18 = 12.5,
12.5 * 30 = 375,
375 - 130 = 245,
So, this is how we get 245.
45 * 5/18 = 12.5,
12.5 * 30 = 375,
375 - 130 = 245,
So, this is how we get 245.
(67)
Lokesh said:
2 decades ago
Actually bridge is a stationary object rite. So speed should be zero. Can u pls explain
Nitin said:
1 decade ago
Why we are subtracting 130 from 375. While train runs on the bridge not off the bridge?
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