Aptitude - Problems on Trains - Discussion

6. 

A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?

[A]. 65 sec
[B]. 89 sec
[C]. 100 sec
[D]. 150 sec

Answer: Option B

Explanation:

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

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


Jeyanthi said: (Jun 3, 2010)  
Since it passes both the poles and the platform , the distance been taken as 890m.(240+650)

Sonam Gupta said: (Jun 15, 2010)  
Please explain all in details.

I'm not getting.

Ramesh Karthick said: (Jun 16, 2010)  
No. It not pass poles and platform. It pass only platform. 240m is train length.

Kirubanidhi said: (Jun 17, 2010)  
First we find speed of the train

speed=distance/time ;distance=240m,time=24 sec

speed= 10 m/sec

the question is how long the train pass the 650m platform

so time = distance/speed;
=(240+650)/10 m/s

=89 sec

Aditya said: (Jun 29, 2010)  
I think answer is 65 sec. Why did you add 240 and 650 no need to add?

Yuvi said: (Jun 29, 2010)  
It may correct. 89sec.

Sujitha said: (Jul 1, 2010)  
Speed= (240*1000)/3600

Do we can calculate like this? is this correct?

Rashid said: (Jul 17, 2010)  
But the train is standing on the platform itself, so its length is included in platform length? what is the need to add 24 and 650.

Saji said: (Jul 19, 2010)  
There is no need of adding 240 and 650..because the question is to calculte the time taken by train to cross the bridge...
so after finding the speed of the train v can calculate directly the time taken by the train by
time=dis/speed
time=650/10
time=65 sec
this may be correct..please suggest me an exact reason why we are adding 650 to 240

Kumar said: (Jul 19, 2010)  
Hi Saji,

You are wrong.

We have to add the length of the train to the length of the platform in order to find the time taken to 'cross the bridge'.


In case of crossing a man/post/pole:

Usually we will ignore the length of man/post/pole. If you want the result speed in 'milli meters/second' accuracy, you can add length of the man or pole to the length of the train.

Indiabix said: (Jul 22, 2010)  
Well said Kumar.

Here 240m is the length of train, 650m is the length of Platform.

If we don't add 240m, we can only calculate the time taken by the part of engine to cross the bridge, not by the entire train.

That's why we are adding length of the train to platform length (distance = length of train + length of platform).

Reference: Important Formulas - Problems on Trains

Saji said: (Jul 23, 2010)  
Kumar thanks a lot. You cleared my doubt. I am confusing this concept for long time.

Himanshu said: (Aug 7, 2010)  
Since the train has to cover the the length of the platform and its own distance..we have too take the total distance of platform and the length of train.

Smita said: (Aug 19, 2010)  
I think this is simple

if
train 240 m long passes a pole in 24 seconds.
i.e 240 m : 24 sec
then 650 m : ? sec

and the ans is is 65sec
may this ans is also correct

will u plz explain why r u add 240& 650?

Prabhakaran said: (Sep 19, 2010)  
The question asked is only How long will it take to pass a platform 650 m long. Why we should add 250? Can any one explain?

Jessie said: (Nov 27, 2010)  
The question is how long the train takes to travel the platform. Then why do we add the train length here? can you please explain. Itz bit confusing.

L.Karthikeyan said: (Dec 3, 2010)  
L.Karthick Said.

Thanks Guys I understand the concept clearly thanks.

Sanjay said: (Dec 8, 2010)  
I think KUmar is correct...

Jellli said: (Dec 11, 2010)  
Hi, I think

1.first we have to find speed of the train
s=240/24=10(in cond of the the train sross the pole)

2.then the same cross the platform of 630m then t=?
s=d/t
t=d/s=(240+650)/10(here we have to add the both len of train and platform)
=89s

Krishna said: (Dec 11, 2010)  
Data is not sufficient where is the pole length ?????
if the train is passing a platform of length 650m
then time taken = (650+240)/speed of train

speed of train = (length of train + length of pole) / 24 sec
= (240 + length of pole)/24 sec
note : 240/24 is not always correct ...

Sumi said: (Dec 12, 2010)  
Why do you want the pole length here you just wana find the length of the platform we use the pole length as the reference point only to calculate the length of the train for platform instead of pole length add the platform length.

Tulsi said: (Dec 28, 2010)  
The distance taken by the train is nothing but the time taken by the train to cross the pole so ... the train passing the pole(time) is 24sec.
ie 240m ->24
slly
650->65sec.

The total time taken by the train to passing the station is=65+24=89sec.

Tulsi said: (Dec 28, 2010)  
The distance taken by the train is nothing but the time taken by the train to cross the pole so ... the train passing the pole(time) is 24sec.
ie 240m ->24
slly
650->65sec.

The total time taken by the train to passing the station is=65+24=89sec.

Dharmendra Isit said: (Dec 30, 2010)  
The answer will be 65 only bcoz
train which is 240m long passes a pole in 24sec

so the speed of train is 240/24=10m/s

when speed of train is 10m/s then what time it will take to cross the platform which is 650m long i.e 650/10=65sec


two distance will be add when question will be like this

A train 240 m long passes a platform which is 650m long in 24 seconds the speed of train is?

Hitesh said: (Jan 30, 2011)  
We add both of them because we have to calculate the time taken to cross the platform. 240 is the length of train. So total distance, the engine has to cover is 240 (train length) + 650 (platform length).

Saiyam said: (Feb 12, 2011)  
Length of platform = 640m
and entire train length = 240m
the Q. is we have to find time taken by train to pass entire platform.
so we include train length utill its last coach passing the platform.
time considered up to its last coach left the platform.
ok.

Vels said: (Feb 23, 2011)  
Anyone explain

They are asking 650 only know. Then why we are adding 240+650.

Ravinderreddy said: (Mar 3, 2011)  
Why to add train length &platform length?

Sarah said: (Mar 17, 2011)  
@Kirubanidhi

Thanks for the clear explanation.

Madhu said: (Mar 28, 2011)  
Here starting position (source) is train length and ending position is platform length (destination) ok.

Pardhu said: (Apr 3, 2011)  
Here train passing both the pole as well as the plate form ....
in question they clearly mentioned pole passing time in seconds only......
so we have to solve first 240/24 =10sec..
and than
(240+650/10)=890/10=89 sec.......

Pankaj said: (Apr 9, 2011)  
Shouldn't it be 650+(240*2)?

Taj said: (Apr 9, 2011)  
I'm so confused answer is 65 or 89.

If you sat 89 how it is come?

Kiran said: (Apr 12, 2011)  
Guys I'm new to here can u ppl plz help....

Whyy can't i solve dis problem in disz way...

240 meters in 24 secs..
650 meters means ??

(650*24)/240 = 65 meters...

is this wrong ....

plzzz help me...

Koteswararao said: (Apr 25, 2011)  
In order to determine the speed the distance of the train can we ignore the distance between the train and the pole.

Neetu said: (May 30, 2011)  
We are adding 240 and 650 because the train needs to cross the entire platform. CROSSING means the last coach should cross the end of the platform. That's why we are adding both lenghts.

Kiran,

We cannot solve in your way because a train will never take the same time in crossing a pole and a platform. The train crossing the pole and crossing the platform is not same.

Pavan said: (Jun 18, 2011)  
Pavan,

hello dudes there is a simple common sense
The length of the train is 240m
The length of the platform is 650m
So the total dstn to cross is (240+650)
=890m
ther fore
890/spd
=890/10
=89sec

Kartikey Patel said: (Aug 6, 2011)  
I think in question ask the time taken for only bridge 650. Then why we add both?

Hari said: (Aug 10, 2011)  
Dudes,
Actually the length is calculated along with the train only as (650+240). The passing of the platform is for the train, so that, train tail has to pass the platform; Henceforth,
(Train+ Platform)is correct

Umesh said: (Aug 10, 2011)  
A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?

=====> for the tail of train to clear the platform it has to pass its own length + platform length.(240+650=890 m)

for 240 m. -- 24 sec.
for 890 m
by observation 890 is @ 4 times (some less) to 240
so time is also @ 4 times of 24 (some less) i,e. 96
from options 89 is @96 & somewhat less.

Suki said: (Aug 24, 2011)  
Neetu's explanation s very nice.

Viji said: (Aug 28, 2011)  
Neetu your explanation cleared my doubt. Thanks.

Devanshu said: (Aug 29, 2011)  
Its not mentioned in ques that train passes pole and platform both. There is no need to add 240 with 650.

Tasauar Rabani said: (Sep 17, 2011)  
Neetus explanation is excelent.

Kavi said: (Sep 28, 2011)  
@Kartikey Patel & Devanshu
First Me too Think like this
if
train 240 m long passes a pole in 24 seconds.
i.e 240 m : 24 sec
then 650 m : ? sec
650*24/240=65

and the ans is 65sec
....
After Saiyam Explanation i got clearly...
bfe netu he expn.
"so we include train length utill its last coach passing the platform.
time considered up to its last coach left the platform."
Thanks...

Hannan said: (Dec 9, 2011)  
By the information given, can you find out the length of pole?plz inform me.

The Guide said: (Dec 15, 2011)  
For problems on trains for most of the problems we use one formulae

time=(l1+l2)/s1+s2

for eg in the above problem

given length of train 240m and time 24 sec then speed=10m/sec

given length of platform 650

their is no speed s2 because platform is a stationary object

so substitue all the values in above formulae

we get time t=(240+650)/10= 89sec

Durg@.. said: (Jan 10, 2012)  
Guys.. i can suggest u one thng that don't depend entirely on formulas, try

to analyze these type of problems logically..

coming to the prblm..

length of train = 240 mts

time taken to cross reference point(pole) = 24 sec

by the basic formula speed=length/time= (240/24) = 10 m/sec

they are asking the time taken by the train to cross the platform

imagine

------------------------- its a platform
650 m
______________ its train
240 m

train is said to be crossed the platform only if the entire train has pased over from it ryt... so clearly the total length that has to be travel to cross the platform is= (platform length + train length)

i.e. 650+240=890 m/sec

and again from the basic formula time= length/speed = 890/10 = 89 sec

Rahul said: (Jan 10, 2012)  
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: (Jan 31, 2012)  
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: (Feb 15, 2012)  
Thanks Kirubanidhi for the right explanation :).

Shro said: (Feb 15, 2012)  
Thanku Rahul for clearing Confusion :)

Vino said: (Apr 4, 2012)  
@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: (Apr 12, 2012)  
Total distance= Total length of train + Length of platform

Satish said: (Apr 21, 2012)  
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: (Jun 5, 2012)  
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: (Jun 8, 2012)  
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: (Aug 14, 2012)  
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.

Vijay said: (Aug 20, 2012)  
As per the given data,the question didn't tell about the pole is on the platform or not.
so,speed = distance/time
speed = 240m/24sec
= 10 m/sec
here speed is same to cross platform as well as pole
so,
D1/T1 = D2/T2
240m/24sec = 640m/T2
10 = 640/T2
T2 = 64 sec

Vijay said: (Aug 20, 2012)  
How can u know that the pole is on the platform.
if the pole is not on the platform,the ans is 65

240/24=650/t2
t2=65

Pooja said: (Sep 27, 2012)  
Can any tell me why there is need to add 240 ?

Akhila said: (Oct 24, 2012)  
@Pooja.

Here we must add 240. Because the total length is expressed as length of the train + length of the platform.

(i.e) 240+650=890.

Eswar said: (Oct 30, 2012)  
240m=24sec.

890m=?

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

=24*890/240.

=89.

Chandu said: (Feb 17, 2013)  
650/240=x/24 and x=65sec then total time is 65sec +24sec=89sec.

Jawahar said: (Mar 13, 2013)  
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.

Vipul said: (Apr 5, 2013)  
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.

Mayur said: (Jul 2, 2013)  
@Vipul.

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

Vijay said: (Jul 12, 2013)  
I can't understand why we want to calculate both the length of train & length of platform.

Please explain.

Sikkanthar said: (Sep 1, 2013)  
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.

Gaurav said: (Nov 13, 2013)  
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.

Sudipta said: (Nov 16, 2013)  
If the train cross the platform i.e it crosses own length.

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

Rajesh said: (Jan 2, 2014)  
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.

Jitendra Barod said: (Jan 8, 2014)  
Speed = 240/24 = 10.

Speed = total distance/time.

Time = total distance/speed = (240+650)/10 = 89 sec.

Kishor said: (Jan 19, 2014)  
For speed of the train (assume Z).
[distance = speed x time].
240 = Z x 24.
Z = 240/24.
Z = 10m/sec.

Let assume time is Y,
Length of the platform = (speed x time) - length of train.

650 = (10xY)-240.
Y = (650+240)/10.

Y = 89sec.

Leela Venkateswara Aro said: (Feb 11, 2014)  
Let length of the train=l=240m.

Time taken to cross platform=t=?

Platform length=a=650m.

Speed of the train=S= (length of the train+length of platform)/time taken to cross platform.

s = (240+650) /t.

s =240/24=10m/s.

10 = 890/t.

T = 890/10 = 89sec.

During this time the train has to cross its own length as well as platform length.

Vatsal Patel said: (Mar 5, 2014)  
I think many people are confusing why we add train length here. The train crosses the bridge means that initially its engine was at starting of the bridge and when it has crossed the bridge, the last bogy of the train is on the other end of the bridge. And engine will be quite ahead by the length of train. So actually the train travels the distance 240+650 in this case when we consider only its engine for ease.

Pon said: (May 23, 2014)  
Let length of the train = l = 240m.

Time taken to cross platform = t = ?

Platform length = a = 650m.

Speed of the train = S = (length of the train+length of platform)/time taken to cross platform.

s = (240+650) /t.

s = 240/24=10m/s.

10 = 890/t.

T = 890/10 = 89sec.

Chandu said: (Jul 4, 2014)  
I got a doubt!

Train length = 240m.

Here in this case platform is independent of train length it is just the speed!

So I feel 65 sec is the answer.

Any suggestions please!

Mallikarjun said: (Jul 5, 2014)  
24 ........> 240.
? ........> 240+650 = 890.

89 sec.

Nagesh Shirsat said: (Jul 19, 2014)  
Well the question is how long train take to cross the platform, in order to do so, train has to cover total length of platform i.e. 650 m and its own length i.e. 240 m, hence 240+650/10=89. 65 is when the engine crosses the platform, it has got to travel train length too to cross the platform entirely. I hope all doubts are clear now.

Bunny said: (Aug 21, 2014)  
By adding 240+650, it says the distance travelled by the whole train to cross the platform.

Rajesh Lodhi said: (Aug 27, 2014)  
Please solve this question.

A passenger train, 150m long.

Passage a railway platform 200 m long in 34 sec time taken by this train to pass a stationary man is.

Please help me anyone me to solve this question systematically.

Divyan said: (Sep 11, 2014)  
Why we can't minus 240 and 650. Please. Help me to know when should we add and when should we minus?

What is the meaning of engine crossing in 65?

K.Anusha said: (Sep 12, 2014)  
Please explain 240+650/10?

Basavaraj S G said: (Sep 19, 2014)  
Hello guys.
W.k.t, speed = dist/time.

So on comparing,
Dist/time = dist/time.
240/24 = (240+650)/t.
t = (890/24)/240.
t = 89 sec.

Manoj said: (Sep 20, 2014)  
Time taken by a train of length l meters to pass a stationery object of length b meters is the time taken by the train to cover (l + b) meters.

So its (650+240)/100.

Arun said: (Oct 20, 2014)  
I think that if they asked how long it will take to cross the pole and platform means 89 is correct but platform alone means 65 because speed of the trains 10m/s.

Sudarsan said: (Dec 12, 2014)  
Given train distance is = 240 m.

Platform distance = 650 m.

Speed of train = 240/24= 10 m/s.

Let the platform be AB = 650 m.

And train length be CD = 240 m.

The time taken is 65 s for D of the train (the front part).

Thus for the train to completely pass i.e. C to pass the total distance is (240 + 650 m).

Thus time taken for the train to pass is 89 s.

Vicky said: (Apr 3, 2015)  
I'm thinking that if it takes 24 seconds to cross 240 m.

Then it takes 48 sec s to cross 480 m with constant speed.

So it takes 240 m = 24 sec.

10 m = 1 sec.

To pass 650 m it takes 65 secs. I'm sure whether this is correct or not. I'm sure that question is not clear.

Riya said: (May 7, 2015)  
Yes it takes 65 secs for the front part of the train to reach the platform end but what we need to find is the time taken by the complete train to pass the platform.

i.e. we need to add the time taken to travel a distance equal to its own length.

i.e 65+(240/10) = 89 seconds. 65 seconds is definitely not the answer.

Raja said: (Jun 9, 2015)  
The time taken by the train to cross the pole so the train passing the pole (time) is 24sec.

240m = 24secs.
650m = 65secs.

The time taken by the train to passing the station is 65+24 = 89sec.

Givid said: (Jun 11, 2015)  
240+650/10.

Why do we divide it by 10 sec finally?

Brindha said: (Jul 10, 2015)  
Platform: 650 m

Train: 240 m.

If we didn't add distance it means. 65 seconds but the train still in platform.

So add the time to cross the pole with that. Now the correct time is 89 sec.

Brindha said: (Jul 10, 2015)  
Train distance + Platform distance = Total time.

Train speed, hence 240+650 = 89.

Speed = 10 m/s.

Brindha said: (Jul 10, 2015)  
Because 10 m/s is speed of train.

Distance = speed/time.

(240+650) = 10/T.

890 (distance).
Time (T) = ?
10 (speed).

Time = 89 sec.

Swamy said: (Aug 21, 2015)  
Well,

24 sec ---- 240 mt.

? sec ---- ((650+240)*24)/240 = 89 sec.

Bishal Gupta said: (Sep 23, 2015)  
If 89 sec is the answer then the 890 m long. It is solved answer said 10 m/s. So if the train is 650 m then 65 sec will be the answer.

Manoj Kumar said: (Oct 13, 2015)  
In the question, they have not mentioned that the pole is also on the platform, then how should we consider the train length upto pole also?

Soumya Biswas said: (Oct 23, 2015)  
The train of 240 m long passes a platform of length 650 m, that means it crosses its own length and the length of platform together.

Ashwini said: (Dec 24, 2015)  
We have to add train length because train has to travel the whole length of platform and it has to cover it's own length.

Asiri said: (Jan 17, 2016)  
The train is 240 m long. Therefore we add (650+240) together.

Bappy said: (Apr 1, 2016)  
As the length of trains is smaller than bridge so here train has to cover his as well as bridge distance. If the length of trains was bigger than platform then only by covering train's length platform length can be passed.

Panasa Harish Kumar said: (Apr 3, 2016)  
Dear Friends,

Train (240meters) Pole Platform (650 Meters)

T moving -> 10sec --> Train left platform.

240 + 650/10 = 89 sec.

Speed = distance(length)/time.
Speed = 240/24 = 10 m/sec.

Vipin said: (Apr 9, 2016)  
Easy tips!

240 + 650 = 890/10 m.
= 89.

Natraj said: (Jun 5, 2016)  
d = 240, s = 24 sec. Total d = 650, Speed = ?.

d = total d + d = 650 + 240 = 890.
Speed = d/t = 240/24 = 10 m/s to pass a platform.

d = 650, Speed = 10 m/s, t =?
t = d/s = 890/10 = 65 sec

Even I have 65 sec as an answer. Then how to get 89 sec? Please help me.

Pravin said: (Jun 19, 2016)  
@Natraj.

Please read your last line carefully,

That is d/s = 890/10 and the answer is = 89.

Milesh Bhange said: (Jun 26, 2016)  
Don't forget to add trains length, question is asking answer about how much time it will take to cross a platform means train will star platforms one end to another in 65 seconds and what about trains end means its length 240 meter question said how much time it will take to cross a whole train means trains end. You have to add 240 its trains length.

Hariharan said: (Jul 7, 2016)  
Which is the right answer 65 or 89?

Please help me.

Triveni said: (Jul 22, 2016)  
@Yuvi.

How? Briefly, explain your answer.

Mir said: (Jul 25, 2016)  
We have to add both. Very simple, a train with 10 coaches will take a longer time to cross the platform as compared a train with just 3 coaches of the same length.

Sidhartha said: (Jul 25, 2016)  
The given answer is wrong.

Train length + platform length + train length = 240 + 650 + 240 = 1130 = the distance to be covered to cross the platform.

Time taken is 1130/speed (10m/s) = 113 sec.

Sidhartha said: (Jul 25, 2016)  
The given answer is wrong.

Train length + platform length + train length = 240 + 650 + 240 = 1130 = the distance to be covered to cross the platform.

Time taken is 1130/speed (10m/s) = 113 sec.

Shailesh said: (Jul 30, 2016)  
The given answer is correct.

We can be said the train passes only when the last engine is cross the platform. So the length of platform and length of the train is right.

Yash Mehta said: (Jul 30, 2016)  
Why you didn't add twice the length of the platform?

Mustapha said: (Aug 11, 2016)  
The answer is just about a simple proportion.

Deeksha Verma said: (Aug 12, 2016)  
I also think 65 sec is correct. 240 m is the length of the train.

Rohit said: (Aug 25, 2016)  
89 is the correct answer. Because the question is time taken by a train to cross the bridge, here 650m is the length of the bridge and 240m is the length of the train so 650 + 240.

Ayush Jain said: (Sep 6, 2016)  
I think that the and should be 65.

Since we have to take out speed and then to put in another.

Leena said: (Sep 12, 2016)  
Why did'nt we multiply the speed by the terms 5/18?

Ie. 240 = (x * 5/18) * 24.

x = 36 so the speed of the train will be 36 m/sec.

Rakes said: (Sep 17, 2016)  
I think it's like this that if the train will pass a man means pass its own length.

So velocity, s = 240/24 = 10 m/s.

Let it passes then platform in x sec.

10 = 240 + 650/24 + x.

So, x = 65.

Pritam Mohanty said: (Sep 22, 2016)  
When the end of the train crosses the station then it is considered to cross the station. For this reason, we need to add the length of the platform with the length of the station.

Subhash said: (Sep 29, 2016)  
I think the answer is 65 sec.

Suppose:

=> 240m
Require time 24sec.

So time = 240/24 = 10m/s.

It means train speed is 10 m/s.
=> 650m.
So time = 650/10 = 65 sec.

It will ask only for 650m length.
Not consider total distance.

Monir said: (Oct 18, 2016)  
240 m passes in 24 sec.
1 m passes in 24/240.
890 m passes in 24 * 890/240 = 89 sec.

Shakir Saifi said: (Oct 25, 2016)  
The answer should be 65 because in this question only asking about how much time take to pass 650 mtr platform not the both platform.

Fiza Khan said: (Nov 1, 2016)  
Can anyone tell why we add 240, while the question is only for 650?

Momena said: (Nov 3, 2016)  
In case of passing a pole,

length of the train = speed * time.
So speed = 240 ÷ 24,
=10 m/s.

In case of passing a platform,
Length of train + length of platform = speed * time.
then,
240 + 650 = 10 * time,
So, time = (240 + 650)/10,
= 89m/s.

Nandhu said: (Nov 12, 2016)  
Pole:
Speed = lengh/time.
= 240/24,
= 10m/s.
Platform:

Time = length/speed.
= (240 + 650)/10,
= 89s.

Santosh Devre said: (Dec 20, 2016)  
65 answer is correct.

I too get the answer as 65.

Akshay said: (Jan 3, 2017)  
Please let me know about the solution.

I'm not getting this. someone help me.

Faisal said: (Jan 18, 2017)  
The solution is correct.

If we don't add 240 we will get only the time taken for the engine to travel and not the entire train.

So we have to add it.

Smitabhutka23 said: (Feb 6, 2017)  
I have a simple solution.
Speed = distance/time;
240/24 = 10 m/s is speed of train.

Now pltform length is 650 m.
We have speed of train nd platform length.
so, time for crossing platform=length of platform/speed of train(t=d/s),
T(time for crossing platform)=650/10 = 65.

Here 65 is the time taken by the part of engine to cross the platform, not by the entire train.
24 second is time taken by train to reach to the pole + 65 sec is time tacken by train to cross the platform = 89 sec.

Binjith said: (Mar 11, 2017)  
Speed = total (distance/time).
240/24sec = 10 ms.
So, 650/10ms = 65 sec.

Balaji.P said: (Mar 13, 2017)  
I think we don't need to add both the meters of the platform.

Radhakrishnan said: (Mar 14, 2017)  
Why can't the answer be 65 according to my explanation?

Speed of the train=(distance /time).

Hence,
240 ÷ 24 =10.
Speed of train is 10 m/s.
Time =distance /speed of the train.
For a 650m platform hence distance is 650.
Time=650m/10m/s.

Hence,
Time =65 sec.

Gavendra Shah said: (Apr 10, 2017)  
I also think that 65 is the correct answer.

Asr said: (Jun 14, 2017)  
I believe the right answer is 65 Sec.

Because train speed is 10m/Sec and to cross 650-meter bridge it took 65 sec to pass that.

Abhishek Baliyan said: (Jun 18, 2017)  
The answer has to be 89 seconds if it is given that this pole is a point of reference on the platform or bridge but is is not mentioned that pole is on the platform thus both the answers are correct it's a tricky question because of the language of the question (consider the question where we give conditions such as a man is standing on a platform that would help you to understand the concept better).

Aravind said: (Jul 5, 2017)  
I Can't understand. Please explain me.

Mir Rokon Uddin. said: (Jul 13, 2017)  
To me, answer is 41 if the pole and the platform consider separately.

650-240=410.

Now it crosses 240m in 24s.
So, 410m in 41s.
If both pole and platform consider jointly the answer will be 89s. I understood 2nd case. But my Mind also with the 1st case. I think the question is ambiguous. Or am I wrong?

Saketh said: (Jul 21, 2017)  
Yes, you are right @Kumar.

Sreeram said: (Jul 28, 2017)  
Pole is given to just calculate the speed of the train, In the question, nowhere mention pole is on the platform so the answer is 65 m/s.

Sai said: (Aug 10, 2017)  
Since the train has to cross the platform, it is not on the platform. It has to completely cross the platform means it crosses it's length.

Therefore total distance becomes train's length+ platform's length =890m.

Time = 890/10 = 89sec.

Akhil Bhatt said: (Aug 12, 2017)  
89 sec is the correct answer.

Rajiv Sd said: (Aug 18, 2017)  
Here pole consider as a point of reference, but platform not a point if consider engine only cross the platform from starting of platform to end (i.e also consider as crossed) 65 sec is correct, but if consider entire train (engine to the last van) cross the platform end to end length of the platform should be added hence 89sec is correct.

Karthikeyan said: (Oct 7, 2017)  
Why we are adding the time of poles with the time of platforms?

Roy7829 said: (Jan 17, 2018)  
Length of train(distance)=240m
Time=24sec
Formula: length(distance)=speed x time
240=speed x 24
speed=240/24
speed=10sec.

Now it has to pass platform of 650m
The total length of platform =650m
train length = 240m
The total distance the train pass the platform = 650+240=890m.
Because as the train entered the platform(650m) the train remaining part was outside the platform (240m).
So total distance the train cover is 890.

Bhagyarajtk said: (Mar 22, 2018)  
Why did you add 240?

Sarang said: (May 3, 2018)  
Distance= speed * time,
240/ 24=time,
Time = 10s,
Distance= speed* time.
240+ 650 combing distance = 890,
890/10= time,
89 m/s.

Onono Solomon said: (May 12, 2018)  
Here, the question is asking for a specific time taken by the train to pass the platform (650/10 =65) not the total time is taken. If at all they asked for total time, we would add them up (65+24).

Agnel said: (Jun 25, 2018)  
240/24=10,
.:650/10=65+24=89.

Gebrekidan Adugna said: (Jul 3, 2018)  
240=24sec.
then 650=x.
240x=650*24,
240x/240=650*24/240,
= 65m/s.

Rajesh said: (Aug 21, 2018)  
It should be 65 sec only.

Analysis: The speed of the train is the same in both cases. For the constant speed,

(distance/time) in first case = (distance/time) in second case.

240/24=650/x==> x = 65 sec.

Rajesh said: (Aug 21, 2018)  
Here, it should come 890 instead of 650. We should add both the values. So the correct answer is 89sec.

Rosha Gangani said: (Sep 29, 2018)  
The Answer is 65s, because the question in not mention both pole and platform then why we calculate both?

Ando Lawrence said: (Oct 4, 2018)  
Accurate Answer is 89 sec only.

@All.

In case of crossing a man/post/pole:

Usually, we will ignore the length of man/post/pole. If you want the result of speed in 'millimetres/second' accuracy, you can add length of the man or pole to the length of the train.

Pravat Kumar Nayak said: (Oct 12, 2018)  
I think the answer is 65sec.
240m long a pole passes away in 24 sec.
So, Time = distance ÷ speed.

240÷24 = 10 sec.

How long will take to pass a platform 650 m long?

Ans-650÷10 = 65m/s.

Veeru said: (Oct 31, 2018)  
As the train has to pass the platform its length need to be considered so they added 240 to the platform length.

Vagdevi said: (Dec 21, 2018)  
As the train crosses the platform, we have to add the length of the train to the platform length. (remember this the train engine is at the platform starting point).

By using the pole concept in the given problem we can find the speed of the train.

Speed=distance*time.

240/24=10sec.

Because, the train to cross the platform, the total length travelled to cross the platform is equal to the length of the train plus length of the platform,

Speed= (240+650) /10.
= 890/10.
= 89.

Patel said: (Dec 28, 2018)  
I think 65 is correct.
A train 240 m long passes a pole in 24 seconds.
240 is the find measurement where you find the 1 m ratio.
How long will it take to pass a platform 650 m long?
Based on finding the 1 m ratio. you have to find for 650 and that is why 65 is correct.

Surekha said: (Jan 22, 2019)  
There is a way to solve like dis also
s=(D1+D2)/(t1+t2) i.e 10=(240+650)/(24+x).
In this way, we will get the answer 65.

Can anyone tell me, I am right or wrong?

Param said: (Jan 23, 2019)  
Length of train = 240.
Time taken to travell the pole = 24sec.
So V = d/t.
= 240/24,
= 10m/s,

So time taken to travel 650m long platform is;
T = d/t.
= 650/10,
= 65sec(ans).

Anil Tej said: (Jan 29, 2019)  
We need to find the time that will take to pass a platform of 650 m.

Therefore, Time = Distance/Speed.
Speed is not given so need to find speed with given values.
Speed = Distance / Time.
= 240 m/24 sec.
= 10 m/sec.

Now we have Distance and Speed to calculate Time that will take to pass 650 m platform.
Time = (650 + 240)m/10 m/sec.
= 890/10 sec.
= 89 sec.

Note : If a train passes a tunnel, bridge, platform then distance covered by train is Length of the train + Length of tunnel (or) bridge (or) platform.

That's why we are adding Length of train + Length of the platform in Distance while calculating Time.

Should not consider the only Length of the platform(650 m).

Anil Tej said: (Jan 29, 2019)  
We need to find the time that will take to pass a platform of 650 m.

Therefore, Time = Distance/Speed.
Speed is not given so need to find speed with given values.
Speed = Distance / Time.
= 240 m/24 sec.
= 10 m/sec.

Now we have Distance and Speed to calculate Time that will take to pass 650 m platform.
Time = (650 + 240)m/10 m/sec.
= 890/10 sec.
= 89 sec.

Note : If a train passes a tunnel, bridge, platform then distance covered by train is Length of the train + Length of tunnel (or) bridge (or) platform.

That's why we are adding Length of train + Length of the platform in Distance while calculating Time.

Should not consider the only Length of the platform(650 m).

Teja Reddy said: (Feb 2, 2019)  
240÷10 = 24.
650÷10 = 65.
65 + 24 = 89.

Santu said: (Mar 7, 2019)  
240 mtrs -- 24 sec.
890 mtrs-- x sec.

ie..890 * 24/240 = 89 sec.

Vishal said: (Jul 22, 2019)  
I think 65 is the correct answer.

And why we add 240 +650?

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