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 10 of 26.
Subhra said:
9 years ago
L = 45 x 5/18 x 30 = 375 - 130 = 245m.
Arman said:
9 years ago
In 30 second train goes= 45 x 1000 x 30 / 60 x 60 = 375 .
Bridge length = 375 - 130 = 245. Ans. 245.
Bridge length = 375 - 130 = 245. Ans. 245.
RAGHURAM S said:
9 years ago
How 25/2 came?
45 * 5/18 = 25/2?
How?
45 * 5/18 = 25/2?
How?
Amit said:
9 years ago
Here, v = 45 km/hr = 45 * (1000/3600) = 25/2 m/s.
T = 30s.
S = vt = (25/2) * 30 = 375 m.
Now, L = 375 - 130 = 245 m (Ans).
T = 30s.
S = vt = (25/2) * 30 = 375 m.
Now, L = 375 - 130 = 245 m (Ans).
Akhil said:
9 years ago
Hi, can anyone tell me how to solve these type of problems?
I'm a just a beginner in maths. Please help me.
I'm a just a beginner in maths. Please help me.
Harry said:
9 years ago
Speed is 45km/hr
Let's make it to seconds.
(45/3600) * 1000,
=12.5 m in 1sec.
Now let's see it in 30 sec i.e 12.5 * 30 = 375.
So in 30 secs it travels 375 but trains length is 130.
375 - 130 = 245m.
Let's make it to seconds.
(45/3600) * 1000,
=12.5 m in 1sec.
Now let's see it in 30 sec i.e 12.5 * 30 = 375.
So in 30 secs it travels 375 but trains length is 130.
375 - 130 = 245m.
Mounish said:
9 years ago
Length = 130 + x.
Speed = 45 km/hr = (45 * 5/18) m/sec.
Time = 30.
Length =Speed * Time.
= 225/18 * 30.
= 375.
x = 375 - 130.
= 245 m.
Speed = 45 km/hr = (45 * 5/18) m/sec.
Time = 30.
Length =Speed * Time.
= 225/18 * 30.
= 375.
x = 375 - 130.
= 245 m.
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.
Anu said:
9 years ago
130 + x/30 = 25/2.
2(130 + x) = 25 * 30,
260 + 2x = 750,
2x = 750-260,
2x = 490,
x = 490/2,
x = 245m.
2(130 + x) = 25 * 30,
260 + 2x = 750,
2x = 750-260,
2x = 490,
x = 490/2,
x = 245m.
Anusha said:
10 years ago
Here, the formula is:
Time is taken to cross the bridge = length of the bridge + length of the train/speed of the train.
To convert km to m we have to multiply with = (5/18).
Converting km to m:
45 * 5/18 = 25/2.
Assume length of the bridge be x then,
30 = (x + 130)/(25/2),
So by calculating we get the x value i.e length of the bridge.
Time is taken to cross the bridge = length of the bridge + length of the train/speed of the train.
To convert km to m we have to multiply with = (5/18).
Converting km to m:
45 * 5/18 = 25/2.
Assume length of the bridge be x then,
30 = (x + 130)/(25/2),
So by calculating we get the x value i.e length of the bridge.
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