Nusrat Fathima said:
(Sun, Jun 20, 2010 08:56:22 AM)
I have solved this problem in a different way, is this right way to solve?
speed=25/2 m/sec
length of the bridge be x m
total distance = speed * time
x + 130 = 30 * 25/2
x + 130 = 375
x = 245 m
is the above method to solve this problem right?
Please help.
Nusrat Fathima said:
(Sun, Jun 20, 2010 09:07:45 AM)
Hi Uvitha,
Speed=25/2 m/sec
then we find the lenght of the bridge using the formula
distance/time = speed
where distance = length of train + x
Time = 30 sec & speed = 25/2
130 + x 25
------- = --
30 2
=> 245 m
Sai said:
(Sun, Jun 20, 2010 10:12:01 AM)
Hi all, i've solved this problem in anotha way
given,
time=30 sec and speed=45km i.e 45x5/18
so im finding the distance= time x speed = 30 x 225/18 = 375m
thus,the distance travelled by the train is 375m and the length given was 130m
so 375-130 = 245m
Now my question is..could someone insist me that the method followed by me is the right one?
Karthik said:
(Tue, Jun 22, 2010 06:49:56 AM)
Yes fathima you are write.
Nusrat Fathima said:
(Fri, Jun 25, 2010 07:14:36 AM)
Thanks karthik
Sai the method mentioned by u is also a right method to solve the above problem..... Good thinking.
Hi jose, by cross mulyiplication method it will come as
2(130 + x) = 25*30
then 2(130 + x) = 750
then (130+x)=750/2
then (130+x)=375
then x=375-130
then finally ength of the bridge is 245m.
Nattu said:
(Tue, Jul 27, 2010 10:33:54 AM)
But crossing chould mean the whole train should be off the bridge right? So why should we subtract the length of the train?
Rahul said:
(Wed, Jul 28, 2010 04:02:25 PM)
@deepika @nattu
speed= train length + bridge length
----------------------------
time taken to cross
we know train length, speed and time taken. find out bridge length.
Hari said:
(Thu, Aug 12, 2010 12:53:21 AM)
Super.
Atul said:
(Wed, Aug 25, 2010 04:29:32 AM)
Plz give me trick to solve to this. Bcz compny gives 1 minute /question and question is so lengthy, then how can I mange my time.
Mahes said:
(Sat, Sep 18, 2010 08:06:15 AM)
I have solved this problem in a different way, is this right way to solve?
Speed = 25/2 m/sec
Length of the bridge be x m.
Total distance = Speed * Time
x + 130 = 30 * 25/2
x + 130 = 375
x = 245 m
Is the above method to solve this problem right?
Please explain.
Boopathi said:
(Mon, Sep 27, 2010 05:40:10 AM)
Hey how is it possible to come.
2 (130 + x) = 750.
X = 245 m.
Please advice me.
Coolburn said:
(Fri, Oct 15, 2010 09:57:00 PM)
Hi, I had my own solustion on that
45 km/hr
1km = 1000m
1hr = 3600 sec
45 km/hr convert to metter
=45000 m
=3600 sec.
45000/3600
=12.5
Since 30 sec can cross the bridge
=12.5*30
=375-130
=245m
Gkvinodh said:
(Fri, Oct 22, 2010 04:16:30 AM)
How the equation (130 + x) /2 = 25/2 comes ?
Mubeen said:
(Wed, Nov 3, 2010 02:25:10 AM)
@Coolburn
Yep... Quite simple and understandable.
Sunny said:
(Sun, Nov 7, 2010 05:00:05 AM)
Hey boopathi its simple.
2(130+x)=750
130+x=750/2
130+x=375
x=375-130
Therefore x = 245.
Ruby said:
(Fri, Nov 12, 2010 07:25:29 AM)
Hey frnd........i sol dis prob in diff way..
length of train=130m
speed=45km/hr
time=30sec
l=s*t
l=(45*5/18)*30
l=(25/2)*30
l=375
length of bridge=l-length of train
x=375-130
x=245m...........
is dis is rite method????????
Vijay Kumar Kuppani said:
(Sun, Nov 21, 2010 09:06:02 AM)
THE SIMPLEST WAY OF SOLVING THIS PROBLEM
train speed=45km/hr=>45*(5/18)=25/2 m/sec;
25/2 m/sec means
the train can travel a distance of 25/2 meters in 1 sec
1 sec--->25/2mts
30sec--->(25/2)*30=>375meters
therefore the total distance covered by the train in 30 seconds is 375 meters(i,e train length+bridge length)
by subtracting the train length from the total distance we can find out the length of the bridge i,e
375-130=245 meters
Kalimuthu said:
(Wed, Nov 24, 2010 01:39:10 AM)
A train cross 1 hour =45km
so that Trian cross in 1 hour =45000m(1km=1000m)
so that trian cross in3600seconds=45000m(1hour=3600sec)
so that trian cross in one second is 45000/3600=12.5m
now 30 sec cross the bridge 12.5*30=375
so that trian length is 130m
so we proof 375-130=245METERS
Prakash said:
(Tue, Dec 14, 2010 09:07:33 AM)
speed=[45*(5/18)]=25/2 m/hr
time=30 sec
s=d/t
distance= speed*time
(25/2)* 30=375
375-130= 245
is this ryt
Nirmala said:
(Sat, Dec 18, 2010 03:32:39 AM)
Why train length added with bridge length what's the logic behind it?
Why bridge length is not subtracted from train length?
Please clear my doubt.
Sundaram said:
(Thu, Dec 30, 2010 01:10:21 PM)
Because train cross the bridge so we must add the length then only we will get the bridge length.
A.Srinivas said:
(Sat, Jan 1, 2011 11:42:19 AM)
(x+130)/30=(45*5)/18
Mannu said:
(Sun, Jan 2, 2011 11:42:29 AM)
What is the significance of train's length. Since the train crossed the bridge so distance should be of the bridge only. Why that bridge and train added?
Janani said:
(Sun, Jan 9, 2011 09:11:22 AM)
How 5/18 came?plz xplain this..
Murali said:
(Wed, Jan 12, 2011 05:11:42 AM)
@Mannu.
Here we know only length of the train. We have to find the length of the bridge. We know the formula"s=d/t".
Here distance is "L1+L2".
Therefore "s= (L1+L2) /t".
Now we will get the answer.
By adding two distance only we will find the one distance (if you know the one distance then find the length of the train).
Murali said:
(Wed, Jan 12, 2011 05:23:34 AM)
Hai! Janani while converting the distance it will come how means.
I) if you convert km/hr into m/sec then multiplies with "5/18".
Ii) if you convert m/sec into km/hr then multiplies with "18/5".
In this way, above problem the train speed is convert into the km/hr into m/sec. (because the answer is given in the form of meters).
Like this 5/18 will come.
Periyasamy V said:
(Fri, Jan 14, 2011 04:38:09 AM)
I solved my own speed of the train 45km/hr,then change into 45000m/hr,then chang into per second (45000/3600)=12.5 m/sec,then multiple with 30sec,(12.5*30)=375, then mins the train length 375-130=245 i think this s correct......
Raees said:
(Wed, Jan 19, 2011 05:36:14 AM)
Nusrath fathima solved method is better.
Chithu said:
(Wed, Jan 19, 2011 06:17:40 AM)
Very useful methods.
Rajan said:
(Mon, Jan 31, 2011 08:08:37 AM)
Periyasamy is perfectly correct and is the correct logic to solve the problem.
Rohit said:
(Thu, Feb 3, 2011 09:26:57 AM)
< (end-point) train (start-point) >EntreR-----[BRIDGE]---< (end point) trian (start-point) >. When train end point meets bridge end point, according to this time is given 30 sec. So we have to add bridge length + train's length as total distance travelled in 30 sec. Two different way are given to solve this prblm.
Rohit said:
(Thu, Feb 3, 2011 10:27:51 AM)
For just above explanation, bridge end point means, departure point of bridge.
Nathy said:
(Mon, Feb 14, 2011 01:05:01 PM)
Sai's method of solving this problem is too simple and easy to understand. Thanks.
Mannsoorkhan said:
(Tue, Mar 15, 2011 01:38:03 AM)
sai your explanation is clear and better explanation thanks to all
Lokesh said:
(Wed, Mar 23, 2011 08:47:36 AM)
Actually bridge is a stationary object rite. So speed should be zero. Can u pls explain
Mukesh said:
(Thu, May 5, 2011 07:48:00 PM)
Given.....
train = 130m
speed = 45 km/hr or (75/6)m/s
time to cross bridge=30sec
Bcos the time is in sec thtat why we convert time in m/sec by multiplying and dividing 45 by 1000 and 3600 respectively
simple formula is distance=speed x time
=(75/6) x 30
=375 meters
now this distance is the distance which include train length also so less train length from this
=375-130
=245 meters
hence we get the ans
Rajeev R T said:
(Thu, May 12, 2011 03:14:30 AM)
If the train is travelling 45 km per hr, then in one min.it can travel 750m, and in 1 sec it can travel 12.5m. then in 30 sec it can travel 375.00 m. As in 375m the length of the train is included, deduct the length of the train from the 375.00m, i.e 245.00m.
Sarvjeet said:
(Thu, May 26, 2011 11:30:45 AM)
Length of the train= 130.
Speed of the train = 45km/hr.
time=30sec.
lengthof bridge = x+length of train.
x+length of train = Speed of the train *time.
x+130=45*5/18*30.
x+130 =375
x=375-130
x=245
Dgeeraj said:
(Thu, Jun 16, 2011 04:29:25 AM)
Nusrat has right formula to solve this.
Mathsfobia said:
(Sun, Aug 14, 2011 01:59:33 PM)
Nice explanation survjt.
Anshul Patel said:
(Sun, Aug 14, 2011 08:56:49 PM)
Amasing solutions and discussion by you guys but 1 thing I got in mind while coming through few examples is that if some1 is new in solving this type of problems then please draw 1 rough imaginary sketch and then try to solve this type of examples I prefer it to be more easy.
Viji said:
(Sun, Aug 28, 2011 01:30:42 PM)
Vijay kumar your explanation is quite simple and understandable. Thank you.
distance=speed*time
assume length of bridge as x meters
here distance=(length of bridge+length of train)
x+130=45*(5/18)
[ 5/18 indictes conversion of km/hr to m/sec)
we get x= 245 m i.e length of the bridge
Vinu said:
(Sat, Sep 24, 2011 08:50:05 AM)
I've a doubt, if the bridge length is greater than the length of the train, then the train need to travel twice it's length + (bridge length-train length) to cross the bridge, why that factor is not considering in this problem?
Ritesh said:
(Sat, Oct 1, 2011 11:46:57 PM)
I want to ask a simple question, how was to come 25/2 ? please send this answer ASAP.
Madhu said:
(Thu, Oct 13, 2011 08:21:47 AM)
We should convert km/hr to m/sec, so we should multiply the 45km/hr by 5/18,then we get 25m/sec.
Sara said:
(Sat, Oct 22, 2011 06:57:28 AM)
Total distance of bridge is 45Km/hr*(30/360)hrs =45/12Kms
Distance in metres = (45/12)*100 =375 Metres
Distance covered = 375M -130M =245M
I believe this is the quickest way given the time allocated in such assessments.
Kriti said:
(Sun, Dec 18, 2011 07:54:43 PM)
[][][][]```````````````[][][][]
```````````````
Train Bridge Train(and timer
(and timer stops here)
starts here)
<------------------------>
This is distance travelled by train in 30 sec (375m)
<--------------><-------->
Lenght of bridge Lenght of train (130m)
Lenght of bridge = distance travelled in 30 sec - lenght of train
Hence proved. : )
Kriti said:
(Sun, Dec 18, 2011 08:00:13 PM)
@VINU
Exactly that would be the total distance travelled by train in 30 sec
Balurajasekaran said:
(Sun, Dec 18, 2011 08:18:15 PM)
45 km/hr = 12.5 m/s
then the train travel 375 m in 30 seconds
[i.e] 12.5[speed] * 30[total time to reach] = 375[this is the time the train completely out of the bridge]
then the length of bridge is 375 - 130[length of train]= 245
Shahul Hameed.M said:
(Sat, Dec 24, 2011 03:50:19 PM)
Am telling the easy way to solve this problem......
in basic formula is
L=speed*time
here we wanna 2 find length of the bridge so,
L1+L2=speed *time(L1=length of the train,L2=length of the bridge)v can get d ans easily....
Mayu said:
(Mon, Jan 9, 2012 12:06:17 PM)
Yes shahul I like your tact to solve this problem.
Umesh said:
(Thu, Jan 26, 2012 03:24:57 PM)
HI All,
Let's simplify this:
Distance traveled(d) = speed(d) * time(t) taken to travel that distance(d)
Speed is 45km/h.
Since answer needs to be in meter, let's convert Km/h into m/sec.
so, 45*(1000/3600), because 1km=1000mtr and 1hr= 3600sec(60minutes*60 sec per minute).
So, our m/sec speed(s) comes to be 45*(5/18)=25/2mtr per sec.
We have s = 25/2m/sec and t= 30 secs. so d = s*t =375mtr.
Since train itself is 130mtr long it wouldn't travel all 375mtr. So, the distance actually traveled(bridge length)by train is 375mtr- 130mtr = 245mtr.
m/sec
2(130 + x) = 750