Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 6)
6.
A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?
65 sec
89 sec
100 sec
150 sec
Answer: Option
Explanation:

Speed = 240 m/sec = 10 m/sec.
24

Required time = 240 + 650 sec = 89 sec.
10

Discussion:
202 comments Page 14 of 21.

Rajesh said:   1 decade ago
240 m in 24 seconds.

So one second 10 m.

So platform length 650 m. It means the train just reach the end of the platform in 650 seconds. It means train not pass the platform. 240 m train is in platform. Its also going to pass.

So 650+240 = 890 m so. 89 sec. is the answer.

Sudipta said:   1 decade ago
If the train cross the platform i.e it crosses own length.

(own length 240 + Platform 650) = / 24 time = 89 sec its correct.

Gaurav said:   1 decade ago
I think the data in not correct because they were asking to pass only 650m long. But here they are taken 650 + 240 which no where written to take.

Sikkanthar said:   1 decade ago
Here the aim of this problem is to be calculate the time taken of the train to cross 650 m long platform.

So from the given data (distance and time) , we have to calculate what is speed of the train.

(distance or length) / time = speed.

So we can calculate the value of speed.

You don't need to convert into hr. Because you are going to find out the time "in s" so you'll get the answer.

I hope anyone understand how do solve this kind of problems.

Vijay said:   1 decade ago
I can't understand why we want to calculate both the length of train & length of platform.

Please explain.

Mayur said:   1 decade ago
@Vipul.

Good explanation. Your right. Question asked is time required to pass the platform and not to come in platform.

Vipul said:   1 decade ago
Whoever thinks it is 65m, take a look.

length of platform is 650 m long, and length of train is 240m.

Train can't cross the platform by just travelling 650m, it has to travel 240m more so that its last bogie crosses the platform.

Therefore train has to travel total distance 650+240=890m to cross the platform.

And its speed is 10m/s, therefor it will take 89 sec.

Jawahar said:   1 decade ago
Answer should be 65. Because in question it doesn't mentioned as total time to cross. Question itself says that. I don't know why to add both. If they mentioned as "total time to cross" then the answer 89 is true.

Chandu said:   1 decade ago
650/240=x/24 and x=65sec then total time is 65sec +24sec=89sec.

Eswar said:   1 decade ago
240m=24sec.

890m=?

Train length+platform length=240+650=890m.

=24*890/240.

=89.


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