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 8 of 21.

Rahul said:   1 decade ago
If we are asked only the time taken to cover 650 m long platform, then the rigth answer is 65.

If we are asked to find the total time to cover the whole distance (240+650) , then the rigth answer is 89.

Sonal said:   1 decade ago
Can you tell me, why did we get 240 two times?

(Firstly 240/24, then after 240+650/10) So please explain me.

Shro said:   1 decade ago
Thanku Rahul for clearing Confusion :)

Shro said:   1 decade ago
Thanks Kirubanidhi for the right explanation :).

Vino said:   1 decade ago
@sonal,
First we find the TIME of the train. So we get 240/24=10m/1s.
Next we find the total DISTANCE of the train. So we get 240+650=890.
Finally.
Speed=distance/time.
=890/10.
=89sec.

Varun Kumar Saraswat said:   1 decade ago
Total distance= Total length of train + Length of platform

Satish said:   1 decade ago
Train of length 240 mts.....
It covers 240 mts in 24 sec...
During crossing a bridge it has to cover 650 mts additional to 240....
So 240mts in 24 sec
Then (240+650) in x sec
i.e x=24*890/240===>89

Ravi said:   1 decade ago
I am done my way.
If its takes 24s to cross 240m,
So how much it'l take to cross 650m long platform. 240+650=890.
You just put one equation like.
240m=24s.
890m=?, then cross multiplication.
890*24/240=89.

Rasim said:   1 decade ago
We can calculate the train speed by considering pole as a reference point
train length=240m
time taken by a train to pass a pole =24sec
s=d/t
s=(240/24)
s=10m/sec
platform length=650m
we know that
total distance=speed*time
650+240=10*t
890=10*t
t=89sec

Swetha said:   1 decade ago
Here no need of calculating the speed, as speed is same we can directly calculate as below:

(d1/t1) = (d2/t2).

(240/24) = ((240+650) /x).

X=89sec.


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