Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 12)
12.
A goods train runs at the speed of 72 kmph and crosses a 250 m long platform in 26 seconds. What is the length of the goods train?
Answer: Option
Explanation:
| Speed = |  |
72 x | 5 |  m/sec |
= 20 m/sec. |
| 18 |
Time = 26 sec.
Let the length of the train be x metres.
| Then, | x + 250 | = 20 |
| 26 |
x + 250 = 520
x = 270.
Discussion:
41 comments Page 3 of 5.
Alan said:
4 weeks ago
Train crosses a platform
Formula:
Time = (Train Length + Platform Length)/Speed.
Given:
Platform Length = 250 m.
Speed = 72 × 5/18 = 20 m/s.
Time = 26s.
Substitute:
26 = (Train Length + 250)/20.
26 × 20 = Train Length + 250..
520 = Train Length + 250.
Train Length = 520 − 250.
Train Length = 270 m.
Formula:
Time = (Train Length + Platform Length)/Speed.
Given:
Platform Length = 250 m.
Speed = 72 × 5/18 = 20 m/s.
Time = 26s.
Substitute:
26 = (Train Length + 250)/20.
26 × 20 = Train Length + 250..
520 = Train Length + 250.
Train Length = 520 − 250.
Train Length = 270 m.
Sujith.m said:
1 decade ago
(x+250)/26=20 Can anybody explain how to come this?
Sania said:
2 decades ago
@ NISHA
Speed is given 72 kmps. But length of platform is in meters. so we have to change it into m/s.
Speed is given 72 kmps. But length of platform is in meters. so we have to change it into m/s.
Sonam said:
2 decades ago
Ya. But why only 5/18 why not some other numbers?
Donald Pinto said:
2 decades ago
Hi Dinesh Thankyou so much for the explanation!!
Ashok.K.Rathod said:
2 decades ago
Thanks dinesh.
Sonia said:
2 decades ago
why x+250?.....for same direction we take sbtraction....then why it is added?
Yogesh said:
2 decades ago
x + 250 = 520, how 520 has come, please explain.
Savi said:
2 decades ago
Hi @Yogesh the formula is length=speed*time
here l=x*250
speed=72*5/18=20ms
time=26s
Apply formula
x+250=20*26
=520
Now got it
here l=x*250
speed=72*5/18=20ms
time=26s
Apply formula
x+250=20*26
=520
Now got it
Akber said:
2 decades ago
@Sania.
Here platform is stationary that is the reason we are adding.
Here platform is stationary that is the reason we are adding.
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